William W. answered 06/05/19
Experienced Tutor and Retired Engineer
If you put a plane down the center of the pyramid like this:
You would get a triangle in the center that would be a right triangle and you could use the Pythagorean Theorem to solve for the height (x). It would be the square root of 262 - 102 or x would be 24.
From that, you can use the regular volume equation for a right pyramid, V = 1/3Bh where V = volume, B = area of the base, and h = height.
V = 1/3(20)(20)(24) = 3200 cu ft