Perimeter = (2 × Length) + (2 × Width)
Area = Length × Width
Let's call Length 'L'. And call Width 'W'. We know that the Length is 4 times the Width so we can say L = 4W. In order to really calculate the perimeter, we first need to find out what W is, because L depends on W (because it is 4W).
Area = 4W × W
256 = 4W².
256 ÷ 4 = W²
64 = W²
√64 = W
8 = W
Now we can finally find out the perimeter! L is 4W = 4(8) = 32.
Perimeter = 2L + 2W
Peri = 2(32) + 2(8)
Peri = 64 + 16 = 80.
Our answer is 80.