Question

A right rectangular prism has a length of 2 1/2 feet, a width of 3 feet, and a height of 1 1/2 feet. Unit cubes with side lengths of 1/2 foot are added to completely fill the prism with no space remaining. What is the volume, in cubic feet, of the right rectangular prism.

Answer 1

how many 1/2 foot cubes can be added to fill the prism completely?

Answer 2

The volume of the rectangular prism will be given by:
volume=length*width*height
length=2 1/2=2.5 ft, width=3 ft, height=1 1/2=1.5 ft
volume=2.5×3×1.5=11.25 ft³

volume of cubes:
volume=1/2×1/2×1/2=1/8 ft³

Number of cubes that will fit the prism will be:
11.25/(1/8)
=90 cubes