A security fence is to be built around a rectangular parking area of 20, 000 ft². If the front side of the fence costs $20/ft and the other three sides cost $10/ft, solve graphically for the dimensions (to 1 ft) of the parking area if the fence is to cost $7500. See Fig. 7.19.

$20/ft $10/ft 20,000 ft $10/ft Fig. 7.19 Total cost $7500 $10/ft