What is the volume of a frustum of a rectangular pyramid if one base has measurements 6 ft. * 8 ft., the other base has measurements 14 ft. * 18 ft., and the height is 3 ft.? A. 120.98 ft. 3 B. 560.30 ft. 3 C. 409.98 ft. 3 D. 252.8 ft. 3

C. 409.98 ft³

Explanation:

The formula for the volume of a frustum is ...

... V = (h/3) (B₁ + √ (B₁B₂) + B₂)

where B₁ and B₂ are the areas of the bases.

Here, we have ...

... B₁ = (6 ft) (8 ft) = 48 ft²

... B₂ = (14 ft) (18 ft) = 252 ft²

So the volume is ...

... V = (3 ft) / 3 * (48 ft² + √ (48·252) ft² + 252 ft²) ≈ 409.98 ft³