Perimeter is all sides added up together. So as you don't know a side's length you can put it as x and make an equation. x + x + x + 6 + x + 6 = 180 4x +12 = 180 4x = 180 - 12 4x = 168 x = 168/4 x = 42 as length is 6 feet longer than width length is equal to 42 + 6 = 48 feet
