Given:
James built a bookshelf shaped like a rectangular prism.
The length of the base is 4 feet.
The width of the base is 2 feet.
The height of the bookshelf is 5 feet.
We need to determine the volume of the bookshelf.
Volume of the bookshelf:
The volume of the bookshelf can be determined using the formula,

Substituting the values, we get;

Multiplying, we get;

Thus, the volume of the bookshelf is 40 cubic feet.