The volume inside is 27 cu. ft.
The surface area of a cube is the area of each face of the cube added together. There are 6 faces on a cube; 54/6 = 9 sq. ft. for each face of the cube.
Each face of a cube is a square, whose area is given by A=s²:
9 = s²
Take the square root of both sides:
√9 = √s²
3 = s
Each side of the square, or edge of the cube, is 3 ft.
This makes the volume 3(3)(3) = 27 cu. ft.
