Let l be the length of the rectangle and w be the width of the rectangle.
We have the equations:
l = 3w and 2l + 2w = 72;
So, we solve the equation 6w + 2w = 72;
8w = 72;
w = 72÷8;
w = 9 inchesl
l = 3·9;
l = 27 inches.
The dimensions of the rectangle are 27 inches and 9 inches.