Answer: the volume is 27 ft^3
Step-by-step explanation:
We have that the surface of the cube is 54 ft^2
first, remember that a cube has 6 equal faces, this means that each face of the cube has a surface of:
f = (54/6) ft^2 = 9ft^2
each one of those faces has the same length in each side, and the surface of a square is equal to the length of one of the sides squared:
f = L^2 = 9ft^2
L = √( 9ft^2) = 3ft
now, the volume of a cube is equal to the cube of the length of the side:
v = L^3 = (3 ft)^3 = 27 ft^3