The image for this is attached for reference. This problem can be used by the Pythagorean equation. To make solving convenient, let us see only one part of the tent. Hence, one side is half of the tend width which is 16/2ft. Height is 12 ft. The unknown side is the hypotenuse. The answer is:
Perimeter is the addition of all 4 sides and a square as all the same sides. so every side will be the same. so if you divide 216 by 4 you get 54. you can check this by adding 54+54+54+54=216 or 54x4=216
The better bargain is the 4 quarts