Find the Radius
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- čas přidán 7. 05. 2024
- This was a fun question, I hope you guys love it.
Does anybody read these descriptions? I think it would be funny if everybody who read this paragraph commented their favorite color and then their favorite animal. Then so many people in the comments would be confused cause there is no prompt in the video. :-)
engineers: yeah, should be around (9+12). Put a box around it.
If we were in a situation where significant digits came into effect, we'd be ignoring the decimels anyway, and 21.25 rounds to 21.... so, close enough for engineering work :D
I was going to do this xd
Close enough
Multiply it by 3 for safety
If only I weren’t a semiconductor engineer…
i was so confused for a while why it wasnt just 9+12, i think i need to go back to basic geometry classes...
Look again
@@mikey9252 yeah 😭😭
Probably because the arc shaved off some distance of the line formed by 9 cm and 12 cm compared with the radius.
It just isn't a circle, just drawn like one, the values are somewhat wrong as well, to make the problem look more beatifull. Nobody wants to see dirty square roots on his plate.
@@user-gm1ty8vu5v It is supposed to be a quarter circle.
You can actually see that r is slightly more than 21, so the final answer is most satisfying.
Oh hell yeah my friend, same brain cell 😅😂
Wrong
"how exciting" always gets me
Another way to arrive at x = 13/4: Use the intersecting chord theorem by filling out the rest of the circle and extending the 12 cm segment horizontally until it hits the circle’s left side (that will make the chord 12 + 9 + 21 long). Similarly, extend the 16 cm segment vertically to hit the circle’s bottom (chord length 16 + x + 16 + x). Then you have the relation:
(12)(30) = (16) (16+2x), giving x = 13/4.
From there you can also use another formula to find the radius! The formula is x^2 + y^2 + z^2 + t^2 = 4r^2 with each letter representing a segment of intersecting chords, that was how i managed to get the answer. (Be aware that this formula can only be used if the chords are perpendicular to each other)
hey andy i really appreciate you showing all the steps, i know how to do the rest once u do the first few steps but i wish my teachers would show ALL their work when i was learning this stuff. really helpful for those who aren’t familiar with the techniques
i actually tried to get rid of a hair on my screen
Blue jaguar! I like your videos, keep making them 👍
Great animation, If I had this description and animation in grade 2 i probably would’ve understood it!😊
Man, I struggle with this stuff but I’m going to keep trying until it makes more sense.
It's all practice bro dw. Are you in engineering class?
Never stop making uploading i dont know what i'd do without these videos😞
Great explanation of the full process.
All this to add ".25" to the radius, i'd say that is 21.4 without thinking
Then you would be approximately correct
That was pretty slick mate, I enjoyed that.
Im in 6th grade and this guy did it in a way i could understand. good job man!
Thank you so much for these question, I want to be a scientist and you gave me a good practice of math.
Put a box *inside* the quarter-circle; put a box *around* the answer. How exciting!
Blue deer! I ALWAYS read the description box!
Nice one again, keep up the good work
It is best to do it with coordinate geometry as follows
If the center of the circle is the assumed origin then the equation of the circle would be
x^2 + y^2=r^2
Point A which lies on the top end of the 16cm line has coordinates (9,16+k) where k is the clearance of the 16cm line from the ground and the point B on the circle which is the right end of the 12cm line has coordinates (21,k)
We have two equations that correlates R and k. Solve and you are done
that's a prettier way to do it
I mean, its the same solution, since the equation os the circle is literally the Pythagorean theorem with x and y 😅. But everything goes if its easier for u to get the equations this way
Point B has coordinates (21, k), no?
@@ryotoiii7945 my bad...I will correct it
It was really easy, but glad to solve it
Thanks bro
I'm partial to forest green and I love the Manta Ray.
Cool stuff, I always forget you can draw radii as much as you want 😓
Emerald Spider
Red sloth! I find these videos really helpful
I love how you explain seemingly complex thing in a simple way. Nice video Andy!!
Good problem! My solution was identical, so I wonder if there's a significantly different way to approach this.
Gotta admit it did confuse me lol but I liked the part with the yellow gecko :)
Carry a ruler. Measure the lenght of a known line. Measure the lenght of the radius. Use this ratio to get the actual lenght of the radius. Problem solved. Used this shortcut plenty in school and college. Works especially well for MCQs when time is a factor.
I would never solve it by myself, but now i know how,thank you !
Makes sense why it’s not 21. You can’t calculate the bottom line like that because the circle is still curving on the line above the bottom. Explains the decimal
i really like geometry, i can't believe that people can't understand the simpler things like this!
How exciting! Dont you love pink capybaras?
Hello, I am from China and am a middle school mathematics teacher. Can you tell me which software is used for the demonstration? I want to use it for my students，万分感谢
Able to do that by myself, feel like still worthy
Gotta love problem solving.
I watch your videos while I shower so that I always start my day with some math 👍🏽 how exciting
Yes, needing two ways to verify x in simultaneous equations. I got there eventually, but it took me a while to figure out where to make the second equation.
I used a very similar method, but only one variable.
Hey I love your videos! Where do you/dis you go to college?
i solved it in basically the same way, but i just used decimals instead of messing around with fractions.
I eyeballs it at 21.smidge so pretty happy with the result.
One day I will figure out the puzzle solo 😔
turquoise bison man i love this one
The solution is straightforward, but the conversion (to Imperial units) was more complicated.
You mean in football fields?
@@lpi3 I think you got them mixed mate, you mean in hockey stadiums?
@@lpi3 yes football (American football); not football (soccer).
How exciting!
I use these shape video's to help me draw in fusion 360. Thx
Классное объяснение, вы учитель от бога.
Very exiting indeed
Little bit too fast, but very nice. Good job man.
Problem got its own problem.
my favorite colour is honestly beige
and my favorite animal is capybara😀
This is how I did it with video paused, check both triangles, mismatch, go back find my mistake, check again r=21.25 how exciting
That was awesome
Nice geometry problem❤
How exciting 😊
4r² = w² + x² + y² + z²
from what is given, you can deduce, that the values needed are 30, 12, 16 and 22,5
Those values squared are 900 / 144 / 256 and 506,25
Sum of which equals 1806,25
that divided by 4 equals 451,5625
Square root of which equals 21.25 and you are done.
Hey! Just wanted to confirm, do you find it easier to use Pythagorean theorem than to just add 16 and 13/4 in the final step? This is a genuine question I am not trying to be sarcastic or anything.
16+13/4 doesn't give you the whole radius. It's shy by a little piece.
@@AndyMath Oh! Thank you, I noticed the upper part just now.
"It's a little more than 21. Next..."
How exciting indeed!
where do you find these questions?
Nice one
EXCITING. SO EXCITING.
Why are people thinking it’s 9+12. To find the radius u have to draw the line from the center. This problem was actually easier than I thought.
Estimated 21.23, this is why Id fail math another time around. "Eh close enough" is as accurate as Ive ever needed to be
blue and idk about animal but hey your smart.
me: pfff.. 21
look at video length: hmmm
Still don't understand how you solved it but i just went 12+9=21, and then added a little bit.So my answer wasn't bad at 21.2 just from looking at it.
Green octopus!
pythagoras theorem for the win
from what i solved atleast, ima watch how he does it
green narwhal!
Love it!
Agreed.
it's like at least 2 or something
i really thought this video was a joke until i realized the 12 cm line is not hittin the actual edge of the circle
blue capybara
I just make a quick SolidWorks part, that way the answer is always correct and my brain doesn’t hurt…😊
I just stuck a pencil in my eye...
purple, alpaca
I liked the deep RRR xD
deep hard R 💪
I don’t know, cats, big cats, hard to narrow down. Tigers, leopards, lynx, it feels wrong to pit them against each other. Anything feline.
I used calculator for squares and roots i got 21.78125
It's just hits different that i can actually loose marks coz of the approximations as calculators are not allowed in exam😮
Black, Red Panda !
color-grey animal-Dog
Teal beaver.
I read them, but I ain't gonna do it.
How exciting
Amazing
Purple panda heheh
Cool, now find the arc
It's already given to be 90⁰
Finally this question.....
Purple Maned Wolf
Purple Fox
Turquoise crab
green giraffe
Purple axolotl
white mantis
Blue Chameleon
hella clever
Blue giraffes are about 21 cm at birth.
Blue Aardvark.
Or... you could just use the law of sin and solve everything in 4 lines, but i like that you solved this analitycally
Purple vulture!
Orange Seagull
pink squirrel baybeeee