Answer:
(a) 5024 ft³
Explanation:
You want the difference in volumes of two cones with height 16 ft, where the larger has diameter 40 ft and the smaller has diameter 20 ft.
Volume
The volume of a cone is given in terms of its radius as ...
V = π/3(r²h) . . . . . . r=radius; h=height
The radius is half the diameter, so the formula with diameter is ...
V = π/3(d/2)²h = π/12d²h
Difference
The two given cones have the same height, but different diameters. The difference in volumes will be ...
V2 -V1 = (π/12)((d2)²h) -(π/12)((d1)²h) = (πh/12)((d2)² -(d1)²)
V2 -V1 = 3.14(16 ft)/12 × ((40 ft)² -(20 ft)²) = 3.14·16/12·1200 ft³
= 3.14·1600 ft³ = 5024 ft³
The difference in volumes of the two cones is 5025 cubic feet.