. A fence is being built to go around a play area for young children. The builder
 plans to use 138 feet of fencing material to build the fence. He must follow these
 directions when putting up the fence:
 • The play area must be rectangular.
 • The width of the fence must be shorter than the length by 10 feet or less.
 • The length and width, in feet, must be whole numbers.
 List all the possible lengths and widths for the fenced-in, rectangular areas.
 Explain how you found your answers.