Volume of the pyramid = Volume of the sand =525 cu ft
13× Area of the base × Height =525
13× Area of the base ×7=525
Area of the base =525×37=75×3=225 sq ft
Let “s” be the side length of the square base of the pyramid.
Then,
s×s=225
s×s=15×15
s=15 ft
Thus, the side length of the base of this pyramid is 15 ft.