I think the total area's unit is 72 sq.ft when it is the lateral area
then square prism is equal to area of the base x heigth
the lateral area of the square prism formula is
area of the lower and upper base plus the area of rectangle sides or
s for square
r for rectangle
2As + 4Ar = 72
from this equation you will get the side of the square base
just use the formula of area each
let x the side of the square base
2x^2 + 4(8)x = 72
solving for ex using quadratic formula
2x^2 + 32x -72 = 0
x = 2 let choose this value
x = -18 not this value because negative
so you have now side
then use the volume formula for square prism
V = As h
V = 2^2 (8)
V = 32 cu.ft

hope this helps happy valentines day!!!