Explanation:
the volume of a pyramid is
base area × height / 3
the base area here is a square.
we know its perimeter : 18.1 ft, which is 4 times the side length.
so, one side of the square is :
18.1/4 = 4.525 ft
the area of the square is side² = 4.525² = 20.475625 ft²
we also know the height of the pyramid, so the volume is :
Vp = 20.475625 × 28.1 / 3 = 191.7883542 ft³
the rounded volume of the pyramid is 191.8 ft³