#1 There is no area of a cube. There is only a volume.
#2 The formula is \(V = s^{3}\) where s is the side.
Substitute 729 in V since that is the volume.
\(729 = s^{3}\)
Take the cube root and you will get 9.
So the formula is \(V = s^{3}\) and the side is 9.
