Volume is length times width times height. This means that if two of the measures are given, you can set up an equation based on this formula. Your work should look like this:
V = l*w*h
1,575 = 21*w*5
1,575 = 105w (Divide both sides by 105.)
w = 15
This means that your answer should be:
The width of the drawer is 15 inches.
