The length of a rectangular prism is 4 feet, and the width is 3 feet. The volume of the prism is 9 cubic feet. In inches, what is the height of the prism?

A) 6 inches

B) 8 inches

C) 9 inches

D) 10 inches

The formula for volume of a rectangular prism is V = lwh. Plugging in what we have:

9 = 4 (3) (h)

9 = 12h

Now we cancel the 12 by dividing:

9/12 = 12h/12

3/4 = h

However, this is in feet. We must convert to inches:

3/4 (12) = 3/4 (12/1) = 36/4 = 9 inches.