Let x = width <span>length is 8 cm more than three times it’s width so length = 3x + 8 </span> Perimeter of a rectangle = 2(L + W) so 128 = 2(x + 3x + 8) solve for x (width) 128 = 2(4x + 8) 64 = 4x + 8 4x = 56 x = 14 width = 14 cm length = 3(14) + 8 = 50 cm