Answer
$V=27 \text{ in}^3$
Work Step by Step
The volume of the cube with side $s$ is $V=s^3.$ The surface area $S=6s^2$. We know that surface area is $54 \text{ in}^2$. We determine the side $s$:
$$54 \text{ in}^2 = 6s^2$$
$$s^2=9 \text{ in}^2$$
$$s = 3 \text{ in}$$
Now it's easy to find the volume.
$$V=(3 \text{ in})^3=27 \text{ in}^3$$
