OpenSAT

The diagonal of a square divides the square into two right triangles. The diagonal of the square is the hypotenuse of these right triangles. Since the sides of the square are the legs of the right triangles, we can use the Pythagorean Theorem: a^2 + b^2 = c^2, where a and b are the legs of the right triangle and c is the hypotenuse. In this case, a = 5 and b = 5, so we have 5^2 + 5^2 = c^2. Simplifying, we get 25 + 25 = c^2, or 50 = c^2. Taking the square root of both sides gives c = \sqrt{50} = \sqrt{25*2} = 5\sqrt{2}$. Therefore, the length of the diagonal of the square is 5\sqrt{2}.