Hello Melissamv9321, find the lengths of the missing sides if side a is opposite angle a, side b is opposite angle b, and side c is the hypotenuse In this right triangle, you are given the measurements for the hypotenuse, c, and one leg, b. The hypotenuse is always opposite the right angle and it is always the longest side of the triangle. To find the length of leg a, substitute the known values into the Pythagorean Theorem. Solve for a2.