Find the volume of a rectangular box whose length is a-2 inches, width is ‘ a ‘ inches and its height is a+3 inches.

The volume of a rectangular prism, in this case the box, is just length x width x height.

We know all three:
L = a-2
W = a
H = a+3

Therefore the volume is:

Work out the left two terms first:
(a-2)x(a) =

Then multiply the height:


Collect like terms:

Then factorise (if needed)


See how the final answer is the same as the length, witdh and height? That's a good way to check your work.
So the volume is:


cubic inches
or a(a+3)(a-2) cubic inches

Hope this helped