Two sides of a triangle have lengths 12 and 15

Two sides of a triangle have lengths 12 m and 15 m. The angle between them is increasing at a rate of 2 degrees/min. How fast is the length of the third side increasing when the angle between the sides of fixed length is 60°? [Hint: Use the Law of Cosines (Formula 21 in Appendix D).]

[@shikokazuniru5484]

Why do we convert Degree into radians? I don't understand why we convert and when to convert it.

[@kryhaj]

Very helpful. Thank you very much