First off, you will need to know the formula for:
Volume of a cube, which is V= [tex] s^{3} [/tex]
Perimeter of a square (one face of a cube), which is P = 4s
Using the given volume, [tex] 343in^{3}[/tex] you can then calculate the measure of the length of one side of the cube by getting the cube root of the volume. In this case, it is 7in.
Now that you have the length of one side, you can then use it in the perimeter formula and your answer should be 28 in.