Answer:
To use a unit cube, you have to multiply the length and the width just like finding the area of a 2D shape. You will then take your "area" and multiply that by the height of the object.
Explanation:
Example, if I have a rectangular prism that is 10 inches long, 4 inches wide, and 6 inches tall, I can multiply 10 and 4 to get 40. I will then take the 6 inches, and multiply it to 40. 40x6=240. The volume of my prism is 240.
I would also like to point out that you can multiply the factors in any order because of the commutative property