Volume is the measure of the amount of space inside of a solid figure,
like a cube, ball, cylinder or
pyramid. It's units are always "cubic", that is, the
number of little element cubes that fit inside the figure.
The formula for the volume of a rectangular prism is:
Area = l x w x h
l = length
w = width
h = height
For example, the volume of a shoe box (a
parallelepiped that is
4 inches by 6 inches by 12 inches is 4 x 6 x 12 = 288 cubic inches.
This means that it would take 288 little 1-inch cubes to fill the shoe box.