Question

What equation can I use to find the side of a cube whose area is 729?

Answer 1

#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.