Since the perimeter is 96 ft this is for two lengths and two sides.
So the length of one side and one length is 96/2 = 48 ft
Next sum the ratios 7 + 5 = 12
Divide 48 by 12 = 4 (This s the length of '1' ratio).
So the length of 7 ratios is 7 x 4 = 28 ft
and length of 5 ratios is 5 x 4 = 20 ft.
To verify it is correct add the two lengths (20 + 28 = 48) which agrees with the length of one side and one length.
So the dimensions are 20ft x 28ft
