Answer:
Perimeter is equal to all four sides added together.
Length = 3W; L=3W
So
P = 2(W) + 2(L) substitute the equation for length above you get
P = 2(W) + 2(3W) and combine
P = 2W + 6W = 8W; put in what the perimeter is and solve for W
66 = 8W, so W = 8.25
W = 8.25, L = 24.75