How many ways are there to prove the Pythagorean theorem? - Betty Fei

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  • čas přidán 10. 09. 2017
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    View full lesson: ed.ted.com/lessons/how-many-w...
    What do Euclid, 12-year-old Einstein, and American President James Garfield have in common? They all came up with elegant proofs for the famous Pythagorean theorem, one of the most fundamental rules of geometry and the basis for practical applications like constructing stable buildings and triangulating GPS coordinates. Betty Fei details these three famous proofs.
    Lesson by Betty Fei, directed by Nick Hilditch.
    Thank you so much to our patrons for your support! Without you this video would not be possible.
    Steph, Jack Ta, Jose Fernandez-Calvo, PnDAA , Marcel Trompeter-Petrovic, Radoslava Vasileva, Sandra Tersluisen, Fabian Amels, Sammie Goh, Mattia Veltri, Quentin Le Menez, Sarabeth Knobel, Yuh Saito, Joris Debonnet, Martin Lõhmus, Patrick leaming, Heather Slater, Muhamad Saiful Hakimi bin Daud, Dr Luca Carpinelli, Janie Jackson, Jeff Hanevich, Christophe Dessalles, Arturo De Leon, Delene McCoy, Eduardo Briceño, Bill Feaver, Ricardo Paredes, Joshua Downing, Jonathan Reshef, David Douglass, Grant Albert, Paul Coupe.

Komentáře • 2,2K

  • @maixuankhang6254
    @maixuankhang6254 Před 6 lety +4849

    Me:Yo pass the _right angled ruler_
    Friend:You better not to _prove the Pythagorean Theorem_
    Me:

  • @matthewcrawford4316
    @matthewcrawford4316 Před 3 lety +1561

    See I wish more teachers while I was still in school explained the reason why math is so important. The only answer I got when I asked "where would I need this" or "why is this important" was "because its on the test" or "its school mandated" rather than explaing that math is integral to the way the world works and functions. This is way more interesting than I remember it being

    • @RGC_animation
      @RGC_animation Před 2 lety +20

      And it helps remembering things!

    • @SomeRandomDude821
      @SomeRandomDude821 Před 2 lety +42

      This video did not explain how the world works. It was a couple historical examples followed by a few different proofs. If you just want to complain about school, go ahead, but don't disguise it as "this 5 minute video taught me a lot about life."

    • @ambientscience2951
      @ambientscience2951 Před 2 lety +46

      @@SomeRandomDude821 you know people are not needed to be taught they just need a direction to flow in they just need inspiration a way that in which they can relate it
      You will not remember everything thaught in school your whole life maby if you go to acadamiea you will only know stuff of your field even then that not to detail
      We nead to teach how to think not what to think
      Offcourse 5 min is nothing in learning compared to 25 years of school it can never be but the point is how much of it resonates with you

    • @sarahnunez318
      @sarahnunez318 Před 2 lety +1

      This

    • @SportSync_official
      @SportSync_official Před 2 lety +3

      When I asked this: they said it was important so you don’t get scammed when asking for your change.
      8th grade…
      Since then I have figured it out myself and I have actually studied maths myself. I have been teaching myself computer science and have realized the importants of maths even more

  • @jbragg1001
    @jbragg1001 Před 3 lety +582

    1:50 love the attention to detail. “On a flat surface” cause we now know we can make non-Euclidean geometry which breaks these rules by using things like spheres to make a triangle with 3 right angles
    Edit: fixed error pointed out by Hritik

    • @zuza7670
      @zuza7670 Před 2 lety +3

      Woah cool

    • @hritikvaishnav603
      @hritikvaishnav603 Před 2 lety +6

      Yeah thats so right. Cool. -And btw you meant --1:50-

    • @rawanmalatani39
      @rawanmalatani39 Před 2 lety

      @@hritikvaishnav603 that's what he said..

    • @hritikvaishnav603
      @hritikvaishnav603 Před 2 lety +1

      @@rawanmalatani39 oh they might have fixed it now. Earlier it was wayy off. And I got confused af

    • @hirzanabqary
      @hirzanabqary Před 2 lety

      @@rawanmalatani39 yeah the commenter edited it

  • @frohenleid
    @frohenleid Před 5 lety +799

    Here's my prove: Ted Ed made a video about it.

  • @nathalieoshenn9387
    @nathalieoshenn9387 Před 6 lety +9281

    are we not going to acknowledge the fact that einstein came up with a proof of the pythagorem theorem at 12????

    • @nosterdaye3102
      @nosterdaye3102 Před 6 lety +1749

      Yeah, and still some people believe he was bad at maths when he was young. lol

    • @thatoneawkwardgirlonsocial4535
      @thatoneawkwardgirlonsocial4535 Před 6 lety +364

      omg he is the genius of all time.

    • @flyingpenandpaper6119
      @flyingpenandpaper6119 Před 6 lety +737

      Yalena Gloria he is a genius, but proving Pythagoras isn't exactly difficult. It's one of the most basic theorems in all maths (these days)

    • @stardust4001
      @stardust4001 Před 6 lety +21

      Ibno Zizou
      Yep

    • @DiscoDerpAnimations
      @DiscoDerpAnimations Před 6 lety +57

      Flying Swordfish yeah but when it was einstein's time it wasn't

  • @supercanadian0640
    @supercanadian0640 Před 6 lety +4359

    Here's my proof:
    It works

    • @brinckau
      @brinckau Před 6 lety +123

      It's only a proof if you tried all possible triangles. Which is impossible to do, as there is an infinite number of possible triangles.

    • @SirDerpingston
      @SirDerpingston Před 6 lety +20

      uncountably, in fact

    • @shishable5087
      @shishable5087 Před 6 lety +15

      OMG! It does! LOL

    • @whathell6t
      @whathell6t Před 6 lety +6

      The Ace Of Spades Here another proof:
      czcams.com/video/mdU8dyjgXU0/video.html
      The Pythagorean Theorem can be weaponized.

    • @rozaepareza
      @rozaepareza Před 6 lety +38

      That's not how you prove something in math, but it is how you prove something in science.

  • @weckar
    @weckar Před 3 lety +230

    I kind of stumbled upon that first one in high school, but without the second diagram.
    I knew (a+b)^2 =a^2+2ab+b^2, and wanted to visualize what that meant geometrically by creating a square with a+b on all sides, using triangles of surface ab/2.
    4 Triangles of ab/2 made 2ab, so the remainder of the square that wasn't the triangles had to be a^2+b^2.
    Unfortunately I never made the leap that this was also c^2 (because I hadn't even considered that side of the triangles), and therefore a proof of Pythagoras, even though it was right in front of me. Just goes to show you sometimes can only find what you are looking for.

    • @ideiasshop5861
      @ideiasshop5861 Před rokem

      Look at this video This is the best demonstration that i have seen mathematically. Actually i believe pythagoras did this way more than 2000 years ago. czcams.com/video/AnQX3zKq0TU/video.html

    • @monokumasussy9685
      @monokumasussy9685 Před rokem +3

      That’s so interesting!!

    • @Dude-xb3xh
      @Dude-xb3xh Před 7 měsíci +2

      IK you can find so much if you just work hard enough

  • @lessgoo3428
    @lessgoo3428 Před 4 lety +307

    Einstein came up with a proof of the Pythagorean theorem at 12
    Asian baby: hold my pacifier....

    • @shichengrao5314
      @shichengrao5314 Před 3 lety +7

      Er, that’s kind of a myth

    • @farismustafa5389
      @farismustafa5389 Před 3 lety +2

      @@piyushxcoder who's that person?

    • @ripdude3692
      @ripdude3692 Před 3 lety +8

      Yeah meanwhile me an Asian kid searching for solution for every dam question

    • @GauravThakur-hg3ic
      @GauravThakur-hg3ic Před 3 lety +4

      @@farismustafa5389 HE WAS AN INDIAN PHILOSOPHER/MATHEMATICIAN/PHYSICIST BORN IN BETWEEN 4TH AND 6TH CENTURY BCE(UNCLEAR BIRTH DATE).

    • @funkyflames7430
      @funkyflames7430 Před 2 lety +1

      @@piyushxcoder That guy had work that is completely different from Einstein’s.

  • @justinjx3
    @justinjx3 Před 6 lety +3454

    Anyone else notice that their eyebrows are made out of right triangles?

    • @maxsimes
      @maxsimes Před 6 lety +95

      Justin Xia 2:09 is that a right triangle?

    • @KarstenJohansson
      @KarstenJohansson Před 6 lety +41

      It is if you are looking at it from a 3 dimensional view point. But that would be another Ted Talk. ;) Anyway, at least Justin didn't say *all*.

    • @smakyakproductions4466
      @smakyakproductions4466 Před 5 lety +1

      K.

    • @abcrtzyn
      @abcrtzyn Před 5 lety +11

      Pythagoras’ eyebrows at 4:46 are definitely not right triangles, or maybe they never are

    • @czyruszamora5309
      @czyruszamora5309 Před 5 lety +1

      Nerd freak

  • @FarCritical
    @FarCritical Před 6 lety +2825

    The animations of the mathematicians were funny

  • @sat_slaya301
    @sat_slaya301 Před 6 lety +498

    The way that Euclid touches young Einstein at 3:05 makes me feel uncomfortable

    • @LakeReeder
      @LakeReeder Před 4 lety +61

      Einsteins expression is the thing that makes it weird.

    • @kiddecent5107
      @kiddecent5107 Před 4 lety +41

      Why does he stick his tongue out tho like wtf

    • @ri_ir
      @ri_ir Před 3 lety +3

      Lol, the way you stared at me at 9.23 according to my clock made me feel even more uncomfortable 🤭😁

    • @nabin369
      @nabin369 Před 3 lety

      Oh

    • @kiddecent5107
      @kiddecent5107 Před 3 lety +2

      Yeah I realised that but it’s just fucken weird how he sticks his tongue out as soon as a man touches his shoulder.

  • @oldmandave6039
    @oldmandave6039 Před rokem +51

    Glad to see someone young was able to prove this theorem

    • @cinnamonstar808
      @cinnamonstar808 Před rokem

      they are ancient Egyptian. They look Afro-Asiatic Proof once more again = THE TRUTH IS STUBBORN

    • @mr.jitterspam9552
      @mr.jitterspam9552 Před 11 měsíci +4

      @@cinnamonstar808 ???

    • @ellieflavia
      @ellieflavia Před 7 měsíci

      @@cinnamonstar808that makes no sense

  • @DethroneME
    @DethroneME Před 6 lety +1783

    I wish I was high on potenuse.

  • @springbutterfly5769
    @springbutterfly5769 Před 6 lety +773

    Step 1: Take a triangular sandwich of your choice that has a right angle.
    Step 2: Eat it.

  • @SpeckyYT
    @SpeckyYT Před 5 lety +219

    Me: 4:56
    "Did you enjoy this lession?
    If so consider please consider supp-"
    **video closed**

    • @darthvader2994
      @darthvader2994 Před 5 lety +6

      Well clearly not cuz you had time to comment this but ye I normally do that with videos like these

    • @monochromeart7311
      @monochromeart7311 Před 4 lety +14

      I think TedED deserves support, they're giving easy to understand education videos that aren't sponsored and don't have ads....
      And asking you politely to consider isn't like forcing you with "This video is sponsored by Raid Shadow Legends" while watching.

    • @blindvi4849
      @blindvi4849 Před 4 lety

      @@monochromeart7311 they have ads ._.

    • @monochromeart7311
      @monochromeart7311 Před 4 lety

      @@blindvi4849 ads aren't much of an income for many people....

    • @monochromeart7311
      @monochromeart7311 Před 4 lety

      @KARL KFOURY not to mention, they would need atleast 3 videos a month for minimum wage (in America) for a single person (if it's indeed 2K per video)

  • @wyvern132
    @wyvern132 Před 5 lety +2

    In case anyone is using this to learn more math, 1:48 is not quite right. 2a^2=c^2 would imply a/c=sqrt(2), which would make sqrt(2) rational. The graphics makes it look like two of the a^2 squares would fit inside the bigger c^2 square (that triangle looks like it’s a perfect fourth of the square), but the a^2 squares are always just a tad off ... exactly one unit area off actually. You can see for example 2*2^2=8=3^2-1, or 2*5^2=50=7^2+1.

    • @shluckduck5172
      @shluckduck5172 Před 5 lety +1

      a/c is always irrational check for yourself my dear sir

  • @TheScienceBiome
    @TheScienceBiome Před 6 lety +880

    What an insightful video! Keep up the amazing work!

  • @gavmcdonald7684
    @gavmcdonald7684 Před 6 lety +270

    And if my Maths teacher, back in the day, just drew a right angle triangle with 3 squares attached he would have saved both of us a lot of time haha.

    • @NazriB
      @NazriB Před 5 měsíci

      Lies again? Plane Ticket USD SGD

  • @lifeisbeautiful7311
    @lifeisbeautiful7311 Před 4 lety +3

    Indian mathematician name was boudhayana, who described it in his writings shulbha sutras(easy formulas).

  • @xavierthomas5923
    @xavierthomas5923 Před 3 lety +17

    It is also valid for other figures scaled to the sides of the triangle. For example, a circle with diameter equal to the hypotenuse will have an area equal to the sum of the areas of circles formed when the other 2 sides are taken as diameters. Also valid when considering semicircles drawn in the same manner, parallelograms and more.

  • @aClovey
    @aClovey Před 6 lety +437

    4:28 Like anyone got time for that

  • @raeryuko
    @raeryuko Před 6 lety +803

    Hi (Sorry for my bad english)

  • @sibasishsahoo8099
    @sibasishsahoo8099 Před 3 lety +26

    The way, through the funny animations the pythogoras theorem was explained is completely praise worthy. Simply awesome 👍👏😊

  • @marianadarosadearaujo7425
    @marianadarosadearaujo7425 Před 5 lety +26

    Incrivel como tudo na matemática tem uma base lógica. Ela se torna cad vez mais linda pra mim. Espero q um dia o Brasil seja um país conhecido pela valorização da matemática.

  • @pranavarastogi6635
    @pranavarastogi6635 Před 6 lety +491

    Please upload A Riddle

    • @vanshjalora8706
      @vanshjalora8706 Před 6 lety +1

      The Channel yea

    • @animandorscrew9598
      @animandorscrew9598 Před 6 lety +8

      The Channel i dont mind ads
      i dont mind buffer
      But When Ads Buffer
      I Suffer
      And Also : Wtch - Will Magnets Work In Outer Space? In My Chan

    • @williamwindy8191
      @williamwindy8191 Před 6 lety

      MyThoughts yep earth is a giant magnet mate

    • @PrincyRawat513
      @PrincyRawat513 Před 6 lety +1

      The Channel I support you for this

    • @TomSistermans
      @TomSistermans Před 6 lety +7

      I got a riddle for you: What is the creature that walks on four legs in the morning, two legs at noon and three in the evening?
      If you guess it correct you will be king of Thebes and marry your mother.

  • @ContinualImprovement
    @ContinualImprovement Před 6 lety +1637

    I just want to impress random strangers on the Internet.

  • @anonnymowse
    @anonnymowse Před rokem +5

    I saw the water-filled squares proof at the Ontario Science Center in the 1980s and remember thinking to myself, so that's what the square on the hypotenuse means. It was a really meaningful representation.

  • @mcalkis5771
    @mcalkis5771 Před 2 lety +2

    Ηere's my proof (I'm sure it has been found by others many times before, altough I am not sure by whom exactly). I found it accidentally:
    For any right triangle, the trigonometric identity (sinθ)^2 + (cosθ)^2 = 1 holds true for any angle.
    Let "a" and "b" be the adjacent sides and "c" the hypotenus. By expanding the definition of the trigonometric numbers in the identity we get:
    (a/c)^2 + (b/c)^2 = 1
    (a^2/c^2) + (b^2/c^2) = 1
    Multiplying by c^2:
    a^2 + b^2 = c^2 Q.E.D.
    It's definetly not much. But I was super proud when I came across it.

    • @olivernorth7418
      @olivernorth7418 Před 2 lety

      It's not a proof because the conclusion is self contained within your original assumption.

  • @afhdfh
    @afhdfh Před 6 lety +323

    305 proofs. I guess it must be true then... :)

    • @AzagronGaia
      @AzagronGaia Před 6 lety +23

      afhdfh Well ,it was "true" to begin with. This just gave more evidence to prove it is more "true".

    • @tapwater424
      @tapwater424 Před 6 lety +48

      It's true with just one proof.

    • @afhdfh
      @afhdfh Před 6 lety +15

      Yes. But this makes it ultra true! ;)

    • @harshsharma-cd7xw
      @harshsharma-cd7xw Před 6 lety +9

      It said more than 350 proofs

    • @afhdfh
      @afhdfh Před 6 lety +2

      So...?

  • @ethanl886
    @ethanl886 Před 6 lety +110

    I LITERALLY NEVER KNEW "squared" ACTUALLY MEANT A SQUARE LIKE THAT OMG
    *everything makes sense now*

    • @darkhoof69
      @darkhoof69 Před 3 lety +21

      When we just memorize plug-and-chug calculations or use calculators, we'll never understand math at all.

    • @purushottamsinghbhadoria5727
      @purushottamsinghbhadoria5727 Před 3 lety +2

      @Zubeen Bhuiyan It is. You shouldn't just rote stuff without knowing what they actually mean in the real world.

    • @Mana-hd5qt
      @Mana-hd5qt Před 2 lety +2

      It doesn’t necessarily mean that. The area of a rectangle is Its length L times its width W; a square is just a rectangle with equal sides so, L=W, therefore A=L•L or L^2.

    • @ashaydwivedi420
      @ashaydwivedi420 Před 2 lety

      If you have a line of length a, then a^3 would be the volume of a cube with side length a! Tadah

  • @ashutoshmahapatra537
    @ashutoshmahapatra537 Před 5 lety +1

    That background music at 4:56 was awesome. As I had dolby speakers I felt as if it was coming from somewhere else other than my speaker!

  • @sowjanyauppalapati7082
    @sowjanyauppalapati7082 Před 5 lety +78

    TED-ED a day keeps bad grades away.

  • @amanraj1608
    @amanraj1608 Před 6 lety +243

    Ted- How many ways to prove Pythagoras theorem
    Me - By using perpendicular triangle.

    • @vibodhj349
      @vibodhj349 Před 6 lety +3

      lol,Is that even a thing? Maybe a product of your imagination. Cool!

    • @alasterkun9274
      @alasterkun9274 Před 6 lety +3

      Aman Raj Google : funny you should ask

    • @alexhancu969
      @alexhancu969 Před 6 lety +2

      Perpendicular triangle, parallel points, congruent points, 2 non-coliniar points, obtuse point...

  • @billybob7564
    @billybob7564 Před 6 lety +42

    I think that many cultures figured this out is amazing, and that our universe just had this mathematical phenomenon

    • @utkarshninawe97
      @utkarshninawe97 Před 7 měsíci +4

      Yes in India, hundreds of years before Pythagoras, Baudhayan speculated the exact theorem for rectangles.

  • @manudude02
    @manudude02 Před 5 lety +2

    I use a variation of the 4 triangles, set them up like at 2:24, and find the area of the squares. It is a^2+b^2+2ab for the large square, while the contents of that square are c^2+4(ab/2), subtract 2ab from both areas and you get a^2+b^2=c^2

  • @goofydeepfriedcat
    @goofydeepfriedcat Před 3 lety +14

    Me: Triangle could never be square.
    Triangle: **is square**

  • @eskayok
    @eskayok Před 6 lety +11

    I have never commented on a TED-ED video. But I have watched nearly all of them, and this is my comment if I had one for every video put together:
    Wow! Amazing! Keep up the good work! Love the cool art style for this video! I like how you touched on that point! Omg I just learned about that in school! The animations are great! I tried to solve the problem from many differed perspectives, but I didn't know it was that simple! I wish that I could remember all that!...
    My main point is that over the really REALLY long time that I have been watching TED-ED. To all the animators, and all the educators and all the writers and all the people that helped contribute to the amazing videos that you guys upload, Thank You! Over the years I have learned a lot from this channel. And maybe one day, I'll be in one of my own TED-ED video!

  • @nicoleeeeeeeeebiebs
    @nicoleeeeeeeeebiebs Před 6 lety +4

    thank you ted-ed for continuing to enlighten me on topics i was always curious about, but never really finding out.

  • @HamIAm
    @HamIAm Před rokem +4

    Need to update the video now that there is a new method using Trig :)

  • @ramsesll2841
    @ramsesll2841 Před 5 lety +118

    1:32 this Indian mathematician is one of the cutest thing I've seen on the internet recently 😂♥️

    • @mayanksinghrajput2214
      @mayanksinghrajput2214 Před 3 lety +23

      These are known as rishis Or
      Brahmans (those who study rhe universe) and had generally the utmost respect in ancient times🥺

    • @shabanaanjum5131
      @shabanaanjum5131 Před 3 lety +4

      Finally I was looking for this comment 🖤🖤

    • @mayanksinghrajput2214
      @mayanksinghrajput2214 Před 3 lety +17

      @AMAM JAIN I am not sure how you took my comment but I was just being informative about who they were and where they stood inside the culture. I don't mind him saying he looks cute at all🤣🤣🤣

    • @pranabmallick01
      @pranabmallick01 Před 3 lety +7

      These are how Indian priests used to dress

    • @hunainaghai3342
      @hunainaghai3342 Před 3 lety

      @@pranabmallick01 😂😂

  • @kamilabihaidar3806
    @kamilabihaidar3806 Před 6 lety +131

    please do a video about thales

  • @AdrianSpencerElizalde
    @AdrianSpencerElizalde Před 6 lety +87

    Geometry was never really my thing back in high school. I did poorly in proving. Algebra, Statistics, and Calculus are my favourites.

    • @thatoneawkwardgirlonsocial4535
      @thatoneawkwardgirlonsocial4535 Před 6 lety +38

      hears calculus
      *screams in terror*

    • @jellybeanium124
      @jellybeanium124 Před 6 lety +19

      PROOFS ARE THE WORST!
      I was pretty ok in geometry, but whenever I hear the word proof I want to tear something up. (I'm also an algebra person.)

    • @whathell6t
      @whathell6t Před 6 lety +1

      Yalena Gloria That's how Japanese students react after scary tales of this: czcams.com/video/mdU8dyjgXU0/video.html

    • @heatherbryant4197
      @heatherbryant4197 Před 6 lety +13

      Adrian Spencer Elizalde I was the exact opposite. I absolutely loved geometry and logical proofs, but struggled terribly with algebra and calculus. Then again I was skipped ahead a year in middle school, so technically I actually never took Algebra 1 (I never even learned how to factor!) And that screwed up my entire math career. Still, such divisions make me wonder about how differences is personality, thinking patterns, brain structure, etc. may account for different math preferences. Personally, I have always considered myself a "visual learner." I can't play any instruments where I can't look down at what I'm doing, so I excelled only in drums and piano. And even when I play the piano, I can't read sheet music. I memorize the keys and which order to press them in by creating a series of shapes in my mind (e.g. I always think of Für Elise as the "three isosceles triangles song"). Being so visual made Geometry come naturally to me. I wonder what types of minds are drawn towards Algebra, Statistics, and Calculus?

    • @kezkezooie8595
      @kezkezooie8595 Před 6 lety +1

      Trigenometry and calculus were my faves.

  • @euclid9492
    @euclid9492 Před 3 lety +1

    Another proof by rearrangement that ends in an algebraic solution:
    Get 4 exact triangle copies and connect them as in the first step of example one in the video where a square of c^2 is in the center. If we look at the outer square that this forms, the side lengths are (a+b) so it’s area is (a+b)^2.
    Now we need to find the area of all 4 triangles combined 2 different ways and then set them equal and solve.
    1- take the area of a single triangle 1/2 base* height and multiply that by 4. We end up with 2ab.
    2-subtract the inner square from the outer square. This gives us (a+b)^2 - c^2.
    Set method 1 and 2 equal to each other.
    This gives:
    2ab = (a+b)^2 - c^2
    This simplifies to a^2+b^2=c^2.
    QED

  • @terryspence7609
    @terryspence7609 Před rokem

    Super clear and easily understood, thank you!

  • @Kopliop
    @Kopliop Před 6 lety +42

    When you have to learn pythagoras and trigonometry in yr 7

    • @ralzejuicekey795
      @ralzejuicekey795 Před 3 lety +1

      Im on year 8 and we have this as our Special Subject

  • @beethepeople6057
    @beethepeople6057 Před 6 lety +32

    So extremely helpful!! I'm in a graduate level History of Mathematics class, and this video really helped me to understand the Pythagorean Theorem in a different way.

  • @gem1900
    @gem1900 Před 2 lety +2

    wish schools would teach us things like this, it makes learning about math so much more interesting because you can see its real life applications and its actually really fascinating, i think more people would enjoy and excel at math if we were first shows things like this before being taught concepts

  • @abvll5049
    @abvll5049 Před rokem +9

    And now ,in 2023,there is an ingenious trigonometric proof which does not circularly rely on the Pythagorean identity iself in the first place, conceived by 2 high school students.

  • @loszhor
    @loszhor Před 6 lety +4

    the proof @ 1:30 is often used in art, such as figure drawing in this example, when combining parts of the body so that they stay within the correct proportions.

  • @apteropith
    @apteropith Před 6 lety +4

    The geometric demonstrations of it are always neat, but my favourite proof is the one that emerges naturally from complex numbers. It then comes right out of the fundamental arithmetic of multidimensional numbers, all on its own.

  • @accelerator8755
    @accelerator8755 Před 2 lety

    Thanks. Explained in 5 minutes what some teachers struggled to explain on the course of multiple classes.

  • @beingearthling3130
    @beingearthling3130 Před rokem +3

    1:37 that theorem is called "Baudhayana Sulbasutra"

  • @feynstein1004
    @feynstein1004 Před 6 lety +33

    Hmm. This makes me wonder. Did all cultures around the world discover the theorem independently?

    • @jessehammer123
      @jessehammer123 Před 6 lety +1

      I doubt such deliberately un-mathematical societies as the Romans produced any original proofs.

    • @1943rfagan
      @1943rfagan Před 5 lety +8

      @@jessehammer123 The Romans used math heavily lol. They were master architects.

    • @yvesnyfelerph.d.8297
      @yvesnyfelerph.d.8297 Před 4 lety

      Africans certainly didn't discover anything useful. Ever

    • @faristaj2326
      @faristaj2326 Před 4 lety +7

      @@yvesnyfelerph.d.8297 en.wikipedia.org/wiki/History_of_science_and_technology_in_Africa

    • @RooneyK-lp6ve
      @RooneyK-lp6ve Před 10 měsíci

      Yes. Many cultures found it independently

  • @vinit.khandelwal
    @vinit.khandelwal Před rokem +3

    351. Recently a new proof was observed

  • @rogersledz6793
    @rogersledz6793 Před 2 lety +1

    Thank you so much for uploading this video. It is helping me get through the pandemic!

  • @aldente7734
    @aldente7734 Před 6 lety +5

    This was super informative and I'm glad it showed multiple proofs

  • @spongbros
    @spongbros Před 6 lety +45

    _What's the difference between Euclid, twelve-year-old Einstein and James Garfield? Answer: Nothing! They all enjoy lasagna! Stop!_

    • @Kanoemirate
      @Kanoemirate Před 6 lety +8

      They all have right triangle eyebrows

    • @reda29100
      @reda29100 Před 5 lety +1

      They didn't have lasagna at the time! They have played fidget spinner instead!

    • @raspberrycrowns9494
      @raspberrycrowns9494 Před 3 lety

      I was genuinely shocked when I heard James Garfield was a mathematician, I mostly knew him as the forgotten president that got shot by a nutjob

  • @manasmayank5082
    @manasmayank5082 Před 3 lety +4

    Very happy to see an intelligent Indian who derived this theorem .
    Love from India 🇮🇳🇮🇳🇮🇳🇮🇳🇮🇳

  • @jlin0755
    @jlin0755 Před rokem +17

    Who is here after the two teenagers found another way to prove the Pythagorean theoreom using trigonometry?

  • @naja8412
    @naja8412 Před 6 lety +44

    Love these videos

  • @tuele4302
    @tuele4302 Před 6 lety +55

    Even though the Pythagorean Theorem was know before Pythagoras, it was Pythagoras who first gave a rigorous proof, and the concept of a mathematical proof originates from the Greeks. Hence we named it after him. As for the water turntable demonstration towards the end of the video, it is not admissible as a mathematical proof. Lengths are specific rather than general.

  • @theoriginaltimetraveller7597

    Two 18 years in the US figured this out recently. Great achievement!

  • @user-no8dn4bo8y
    @user-no8dn4bo8y Před 2 lety

    Very nice explanation and method, thank you

  • @nadiaidris2017
    @nadiaidris2017 Před 6 lety +13

    I love ted end it makes me feel relaxed when learning new things
    even though I hate maths

    • @alexandertownsend3291
      @alexandertownsend3291 Před 2 lety +2

      You probably don't actually hate math. My guess is you just hate the lazy way it is often presented in schools.

  • @autisnt
    @autisnt Před 4 lety +45

    Me in year 7: Pythagoras
    Me in year 8: Trigonometry
    Me in year 9: Could we use Trigonometry to prove Pythagoras?

  • @ThePiMan0903
    @ThePiMan0903 Před rokem +1

    Thanks for this TED-Ed and Betty Fei!

  • @prashanthkumar0
    @prashanthkumar0 Před 6 lety

    your videos are really appreciative
    thanks for this

  • @oussamanhairech5178
    @oussamanhairech5178 Před 6 lety +5

    I hope you do more videos about math , this is interesting.

  • @emuoo1018
    @emuoo1018 Před 5 lety +3

    I have a simple way to prove the Pythagorean theorem, you have 3 squares, the 1st square has an area of 4cm², the 2nd square has an area of 8cm², the final square has an area of 12cm². If you combine the 1st and 2nd squares, you get an octagon with an area of 12cm² (4cm² plus 8cm2) which is equal to the area of the third square (12cm²)

  • @MinityMaths
    @MinityMaths Před 3 lety

    Very interesting video! The water demonstration is an easy one to remember! 👍

  • @Sanatan_saarthi_1729
    @Sanatan_saarthi_1729 Před 3 lety +2

    I added one method using circles and for your kind information I did it in summer vacation when I was in class 8

    • @Sanatan_saarthi_1729
      @Sanatan_saarthi_1729 Před 3 lety

      I don't know how to send link of my method otherwise I would have posted it

  • @raahilshammin7563
    @raahilshammin7563 Před 5 lety +3

    My solution was to make the formation at 2:25 and then subtract the four triangles from the whole figure.
    (a+b)^2 - 4(0.5ab)=c^2
    (a^2 + 2ab + b^2) - 2ab = c^2
    a^2 + b^2 = c^2
    Another proof that I made was to use the formula that finds the length between two points on a graph and center the vertex of the triangle at the origin and the sides a and b on the x and y axis
    sqrt( (a-0)^2 - (0-b)^2) = c
    (a-0)^2 - (0-b)^2 = c^2
    a^2 - b^2 = c^2

    • @diurnal.quotes
      @diurnal.quotes Před 5 lety +1

      I dont even understand what ur saying lol a+b stuffs

    • @raahilshammin7563
      @raahilshammin7563 Před 5 lety

      @@diurnal.quotes Ok I get that this is probably a joke but just to specify for anyone who didn't see where I got the a+b in solution one, if you look at one of the sides on the whole figure at 2:25, the side lengths are the a and b sides of your right triangle. Because the figure is a square, to find the area you have to square the side lengsths, resulting in (a+b)^2.

  • @rajvirshah
    @rajvirshah Před 5 lety +3

    Take a triangle of sides a,b,c and angles A B C and b is right angled
    Now A+C=90
    now sin(A+C)=1
    SO NOW
    SinAcosC+Cosasinc=1
    b2+a2=c2

  • @matthewhunter2443
    @matthewhunter2443 Před 2 lety +2

    Here’s my proof:
    Take the square from 2:29
    The length of the large square is (a+b) squared because the length of one side of the large square is the length of a plus the length of b, making a square that has a+b as a side length
    The area of c^2 is the area of the large square minus the triangles
    The area of a triangle is ab/2 (because one triangle is a rectangle with side lengths a and b which is cut diagonally) and since there are four triangles, the total area of the triangles is 2ab
    The total area is (a+b) squared, which is a^2+2ab+b^2 and you subtract the 2ab from the four triangles, you get a^2+b^2= the area of the square of c, or a^2+b^2=c^2

  • @jment8149
    @jment8149 Před 2 lety

    Really helped me to understand thank you 👍

  • @krishprayan
    @krishprayan Před 2 lety +6

    pythagorous : i am first to find out this
    indian ancients techers : hold my theorem

    • @krishprayan
      @krishprayan Před 2 lety +2

      @Clint Eastwood pls once see ancient books on hindus , everything in maths science etc etc is written there
      also i am non-hindu but now i am adopting hinduism

  • @GirlsFootballFreestyle
    @GirlsFootballFreestyle Před 6 lety +6

    I love these videos...makes me feel smart

  • @praiseonionrings182
    @praiseonionrings182 Před 6 lety +1

    Here's one I thought of in my head (though I'm sure many others have as well).
    Take the square used in 2:28. The side length is a+b (a long side of a triangle plus a short side) so the area is (a+b)^2=a^2+2ab+b^2.
    The four hypotenuses of each triangle are equal and form a square of area c^2 where c is the hypotenuse. When that square is removed, four triangles are left, with height a and base b, so the area of each one is ab/2.
    There are four of them, so their total area is 4*ab/2=2ab.
    Since these triangle and the smaller square make up the entirety of the large square, the total area of the large square can be written as 2ab + c^2.
    But that same area can also be written as a^2 + 2ab + b^2.
    Therefore, a^2 + 2ab + b^2 = 2ab + c^2.
    Subtracting 2ab from each side yields the result a^2 + b^2 = c^2.

  • @nandakumarcheiro
    @nandakumarcheiro Před 3 lety +1

    Using Alkashy theorem in right angled triangle 90 having two adjascent sides a and b and the opposite side as c ,c^2 = a^2+ b^2 - 2 a b cos theta as cos 90 is zero and hence a^2+ b^2 = c^2 proving pythsorean theorem.

  • @hero9402
    @hero9402 Před 4 lety +5

    I wish I saw this earlier when i was getting introduced to Pythagoras theorem and I hated it. This makes things so much intresting

  • @user-gz5to3ix5q
    @user-gz5to3ix5q Před 2 lety +6

    We learnt the Pythagoras theorem in 5th grade.
    Did you know that there is an alternate, simple and ancient Indian method to compute hypotenuse :
    The Tamil kings, centuries before the dawn of the Common Era had built dams, dykes, palaces and great cities during the Sangam era. How did the architects in those times design and build the great turrets in temples and the great dams,canals, highways, etc.
    Upon searching it was revealed that finding the hypotenuse of a right-angle triangle can be done independent of the Pythagoras theorem, (which enunciates that sum of the square of both sides of the right angle will be equal to the square of the hypotenuse, of the triangle).
    It is a simple task to find the square of a number, but finding the square root of a number is not so easy. There is no simple formula to find the square root of a number.
    An ancient Tamil mathematician/poet Pothayanar, who lived 800 years before the Common Era, had given a quatrain of four lines articulating the method of finding the length of the hypotenuse of a right-angle triangle without the need to find the square or the square-root, only using the length of the sides, and simple fractions.
    Here is the English translation of the quatrain:
    Divide the horizontal into eight,
    Delete one portion, and add the remaining,
    to half of vertical to result you’ve got.
    The answer would be hypotenuse of the triangle.
    The Tamil poem by poet Pothayanar is :
    ஓடும் நீளம் தனை ஒரேஎட்டுக்
    கூறு ஆக்கி கூறிலே ஒன்றைத்
    தள்ளி குன்றத்தில் பாதியாய்ச் சேர்த்தால்
    வருவது கர்ணம் தானே. - போதையனார்
    The advantage of the ancient theorem is that there is no need to use a square / square root function.
    But before we jump to conclusions let us see how this ancient and simple formula works :
    Let us take the three sides of the right-angle triangle to be A, B, and C, where C be the hypotenuse.
    Let us take A and B to be the horizontal and perpendicular
    sides respectively.
    If we are to divide A into eight parts and takeaway one eight, it would be 7/8A.
    The half of the vertical side will be 1/2B.
    Thus, the result should be :
    C= 7/8A + 1/2B
    Let us give some numbers and try :
    *Firstly* Say A=8 and B=6
    By Pythagoras theorem, C equals √ (8x8+6x6) Which is √ (64+ 36) = √100 =10.
    Now, according to the quatrain :
    C should be 7/8 A+ ½ B
    7/8 of A (8) = 7 and ½ of B (6) =3
    Together they add up to give hypotenuse to be 7+3=10

    *Second* let us try with taking A=28 and B=21 then
    by Pythagoras theorem C= √ (21x21+28x28)
    C = √ (441+784)
    which is =√1225 = 35
    According to quatrain : hypotenuse becomes 7/8A + 1/2 B.
    7/8 A=7/8 (28) = 24.5 and 1/2B= 1/2 (21) = 10.5
    Thus 24.5 + 10.5= 35.
    *Third* let us try with taking A= 12 and B= 5 then
    By Pythagoras theorem C= √ (12x12) + (5x5) = (144+ 25) √169 =13.
    According to the ancient Tamil quatrain : the hypotenuse becomes 7/8A + 1/2B
    7/8(12) = 10.5 1/2 (5) = 2.5
    Thus 10.5 +2.5 =13
    Pothayanar must have been a great mathematician, who got lost like fruit hidden in the foliage of the tree.
    The discoveries of the Greek scientists and mathematicians spread far and wide along with their conquests in the world.
    Unfortunately, in ancient India, many great intellectuals, and their knowledge / findings were lost to the world owing to various reasons and events.
    Our schools teach the Pythagoras Theorem to our children. They should also teach Pothayanar's theorem as an alternate and easier method, as explained above.

    • @mahmed4846
      @mahmed4846 Před 2 lety

      Wow Thank you
      So fortunate to learn this
      May I know where did you find this and where can I find treasures like these?
      Thanks again

    • @Thaplayer1209
      @Thaplayer1209 Před rokem

      Doesn’t work with 7,24,25. Or with any right triangle with irrational sides.
      It only works for triangles with ratios 3:4:5 and 5:12:13 which is probably why its not commonly used.

  • @brainstormingsharing1309
    @brainstormingsharing1309 Před 3 lety +1

    Absolutely well done and definitely keep it up!!! 👍👍👍👍👍

  • @user-in7yz3yw2y
    @user-in7yz3yw2y Před 11 měsíci

    Thank you for your explanation! so fun!

  • @limbosup2224
    @limbosup2224 Před 4 lety +3

    Pythagoras: i made Pythagorean theorem
    Al kashi : hold my Scalar Product

  • @hiran1724
    @hiran1724 Před 6 lety +7

    I love Ted ed

  • @davidseed2939
    @davidseed2939 Před 2 lety

    method at 3:41 can also be done by just saying that the area of each triangle is proportional to the square of the hypotenuse. since sum of areas of two smaller triangles is equal to the area of the larger triangle.
    then the sum of the squares of the hypotenuses of the two smaller triangles(a² +b²) is equal to the square of the hypotenuse of the larger triangle ( c²)

  • @jdstones2890
    @jdstones2890 Před 3 lety +1

    Great video very informative!!

  • @ferronzomeren2733
    @ferronzomeren2733 Před 6 lety +11

    but if the angle is not 90 degrees,
    c^2 = a^2 + b^2 - 2ab*cos(gamma)
    whereas gamma is the corner which should be 90 degrees, but is not.
    cos(90) = 0, so a lot of people forget about the second part of the theorum.

    • @crake9510
      @crake9510 Před 5 lety

      Wat?

    • @contaantiga6114
      @contaantiga6114 Před 5 lety +3

      You are talking about two different theorems...

    • @batiwalajehangir938
      @batiwalajehangir938 Před 5 lety

      Pls speak English

    • @Omar_MH
      @Omar_MH Před 5 lety +1

      Different theory. In school we called it the law of cosine whereas the law of sin is (A/sin a) = (B/sin b) = (C/sin c) where A, B and C are the the sides facing the angles a, b and c in that order.
      But both of these are more like expansions to the one in the video.

    • @qc7511
      @qc7511 Před 5 lety

      That's a different theorem. Pythagoras is for triangles which have an angle of 90°. If you're given a non-rectangle triangle, then you should apply Sine and Cosine theorems.

  • @wiseguy7355
    @wiseguy7355 Před 21 dnem +6

    Who's here after teens found a trigometry proof for Pythagorean theorem

  • @alejandrorodriguez4838

    This help so much thank you 🙏🏼

  • @deepakpradhan9904
    @deepakpradhan9904 Před 2 lety

    People know Aacharya Baudhayan born in 800-740 BC was written book on Pythagoras theorem . Aacharya Sushurta born in 800 BC perform many surgery and also written many books on surgical tools , type of surgery , types of diseases , it's cure through different plants . Ancient University of Greek founded in 387 BC platonic , ancient University of India is Taxasila founded in 500 BC , Nalanda University founded in 470 BC and 10 more ancient University founded in India back then .

  • @trantinto
    @trantinto Před 5 lety +16

    I just got so much hype bc of watching this. Felt like my IQ has increased

  • @CuriousConnman
    @CuriousConnman Před 6 lety +4

    Hey, I just heard about the halting problem, so could you help me and everyone else understand? Thanks, Keep making great content!

  • @vedasai4537
    @vedasai4537 Před 3 lety

    The pattern of grey and other colors of squares was cool 😎 keep going great job👍

  • @wheresmypen4644
    @wheresmypen4644 Před 3 lety +1

    The animation makes it look so easy and this theory I never understood in my entire school life

  • @maahichauhan4317
    @maahichauhan4317 Před 6 lety +494

    Do you know Ted ed That today was my half yearly maths exam and I had given this question =prove the Pythagores theorem......I was searching for it for the whole night but didn't get anything.....yar kal upload kr di hotu toh tumhara kya chala jata

    • @shlokagrawal1727
      @shlokagrawal1727 Před 6 lety +81

      Well, I might be wrong, but I think that you have an internet connection.

    • @CivilDistribution
      @CivilDistribution Před 6 lety +5

      Synchronicity, almost.

    • @sloggiare
      @sloggiare Před 6 lety +27

      Did you have a stroke when you got to the last sentence? If that's the case I hope you'll get better...........nah, I'm joking.

    • @sancheetb
      @sancheetb Před 6 lety +12

      Xavier1927 He was writing Hindi (Indian language) in English.

    • @shivamchauhan8381
      @shivamchauhan8381 Před 6 lety +10

      Love the last part 😂😂

  • @Horinius
    @Horinius Před rokem +3

    @1:38 Chinese ancient text mentioned that this relationship was discovered as early as 1000BC. Check on 商高 inside the book called 周髀算經.

  • @darkhoof69
    @darkhoof69 Před 3 lety +1

    Also note that if c is given, you can graph y = ±√(c^2 - x^2) to get a circle. Now you're actually ready to start trigonometry, instead of just pressing sin and cos on a calculator to get an answer.

  • @imtree2464
    @imtree2464 Před 3 lety +1

    I was literally thinking about this and now this was in my recommendation

  • @eocalive
    @eocalive Před 6 lety +13

    BRING THE RIDDLE VIDEO BACK ATLEAST 1 IN A WEEK