Question

a right rectangular prism has a length of 2 1/2 feet and width of 3 feet and a height of 1 and 1/2 feet. Unit cubes with side length of 1 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

The volume of the prism is the product of the area of the base (Ab) by the height (h). In this case, the base is a rectangle, so its area is the product of the two contiguous sides (a · b).
  Therefore, the volume of the prism will be given by:
  V = (2 1/2) * (3) * (1 1/2) = 11.25 ft ^ 3

Answer 2

The volume of the right rectangular prism is the product of all its dimensions, length, width and height. Since all these dimensions are given, therefore, we can directly calculate the volume of the right rectangular prism by substitution to the formula.

V = L*W*H
V = (2.5 ft)(3 ft)(1.5 ft)
V = 3.375 ft³ or 3 and 3/8 ft³