the perimeter of a rectangle is
P = 2w +2l
P = 68 ft
and given the ratio l/w = 9/8 from this result 8l = 9w so l = (9w)/8
P = 2w +2l
68 = 2w +2((9w)/8)
68 = 2w +9w/4
4*68 = 8w +9w
272 = 17w
w = 272/17
w = 16
so than we know that w=16 so than the length will be
l = (9w)/8
l = 9*16/8
l = 9*2
l = 18
so than we know that
l = 18
w = 16