If the volume V = 144 cubic inches, and V = length*width*height,
then 144 cubic inches = length*width*8 inches
and length*width = 144/8 square inches = 18 square inches.
This means that the length and width can be any pair of numbers that has a product of 18.
Examples: 2*9, 1*18, 1/2*36, etc.
Keep in mind that the dimensions aren't necessarily whole numbers! There are actually infinitely many answers to this problem, so think of a way to describe the solution set in general terms.