Question

The cube has surface area 864 in2, so each of its edges has a length of what?

Answer 1

Cube has six sides
864/6 = 144
a square has 4 sides, so your answer is 144/4 = 36.

Answer 2

A=6s^2 and A=864

6s^2=864

s^2=144

s=12 in.