the perimeter of a rectangle is 18 inches what are the possible lengths and widths if the side lengths are whole numbers

The perimeter is (2 lengths) + (2 widths). Since the perimeter is 18 inches, (1 length) + (1 width) must add up to 9 inches.

If the length and the width must both be whole numbers, the only possible choices for the side lengths of this rectangle are:

1 x 8 in

2 x 7 in

3 x 6 in

4 x 5 in.