We will use the Pythagorean Theorem to solve both cases. Case 1: Given sides are both legs of the triangle: 3^2 + 4^2 = c^2 9 + 16 = 25 = c^2 c = 5 Case 2: Given sides are one leg and the hypotenuse: a^2 + 3^2 = 4^2 a^2 = 4^2 - 3^2 = 16 - 9 = 7 a^2 = 7^(1/2) The third side of the given right triangle could be five or the square root of seven.