The longest diagonal is about 8.9 inches. The longest length is going to be between the two longest lengths, the width and the height. The Pythagorean theorem is a^2 + b^2 = c^2. Plug the width and height into a and b of the Pythagorean equation. (4)^2 + (8)^2 = c^2. Now simplify the equation. 16 + 64 = c^2. 80 = c^2. Now find the square root of each side. (sqrt)80 = (sqrt)c^2. If you simplify this, you will find that c is equal to about 8.9 inches.
So we want to find the radius of the circle. So just divide 56.52 by 3.14 and 2, which is 9. And then to find the area, just square 9 and multiply it by pi, which is 354.34 square inches.
