Pythagorean Theorem is my favorite theorem because I really like geometry. When I was in MATH 460 we learned to prove the theorem and use it in the proof of other problems. I like this theorem because I enjoyed geometry and figuring out the proofs. Also, it think it is really cool the way Pythagoras solved the problem, especially for the point in time in which he lived. The Pythagorean Theorem: The square of the hypotenuse of a right triangle is equal to the sum of the squares on the other two sides.