Let L and H represent length and height, respectively. .. 20 ft = (4/5)*L .. L = (5/4)*(20 ft) = 25 ft . . . . . . . . multiply by the reciprocal of the coefficient of L
.. H = (2/9)*(L +20 ft) .. = (2/9)*(25 ft +20 ft)) .. = (2/9)*(45 ft) = 10 ft
The volume is the product of length, width, and height. .. V = (25 ft)*(20 ft)*(10 ft) = 5000 ft^3