The volume of a cylinder is given by V = πr²h We want 80% of the volume that would be obtained using h=6 ft. So, our volume of interest is v = 0.80*π*(18 ft/2)²(6 ft) v = 388.8π ft³ v ≈ 1221.45 ft³
Ben will put about 1221.45 ft³ of water in the pool.
