Pythagorean Theorem

The Pythagorean Theorem states that for all right triangles, a^2+b^2=c^2, where c is the long hypotenuse, and a and b are the legs of the right triangle. This theorem is a classic to prove, and hundreds of proofs have been published. The Pythagorean Theorem is the most frequently used theorem in geometry, and is one of the many tools in a good geometer's arsenal.