Back when you first studied square roots and how to solve radical equations, you were probably introduced to something called "the pythagorean theorem". this theorem relates the lengths of the three sides of any right triangle. the legs of a right triangle (the two sides of the triangle that meet at the right angle) are customarily labelled as having lengths "a" and "b", and the hypotenuse (the long side of the triangle, opposite the right angle) is labelled as having length "c".