A diagonal of a square is 36 feet long. What is the area of the square?

So you can you the Pythagorean theorem to solve this problem.

if each side of the square is a certain length x, then the square is made up of two right triangles.

the sides adjacent to the right angle are length x while the hypoteneus is the diagonal whcih measures 36 feet.

a^2 + b^2 = c^2

x^2 + x^2 = 36^2

2x^2 = 1296

x^2 = 648

x = 25.456

area of a square = x^2 = 648 ft^2