Set up variables:
l = length
w = width
p = perimeter
A = area
Relations:
A = lw
32 = 2l + 2w (perimeter)
l = 3w
Find the missing info:
32 = 2(3w) + 2w (solve for w)
32 = 6w + 2w = 8w
w = 32/8 = 4
If width equals to 4, then length would be 4 * 3, 12.
Area = 12 * 4 = 48
