Question

Identify the volume of the composite figure rounded to the nearest tenth.

Answer 1

Answer:

  (c)  115.2 ft³

Step-by-step explanation:

The volume of a composite figure can be found by decomposing it into figures whose volumes are easy to compute. Here, the figure can be nicely represented as a cube and a square pyramid.

__

Cube

The volume of the cube on the left is given by ...

  V = s³

  V = (4.2 ft)³ = 74.088 ft³

__

Pyramid

The volume of the pyramid on the right is given by ...

  V = 1/3Bh . . . . . where B is the area of the square base

  V = 1/3(s²)h = (4.2 ft)²(7 ft) = 41.16 ft³

__

Total

The volume of the composite figure is the sum of these volumes:

  cube volume + pyramid volume = 74.088 ft³ +41.16 ft³ = 115.248 ft³

The volume of the composite figure is about 115.2 ft³.