Since all the sides have the same length, it means that a×a×a will equal 384 cubic cm, where a has the same value.
We need to find the number that cubed, will give us 384.
Thinking of the closest number that would give us something close to 384, it's 7 cubed, which is 343. Therefore, it must be something over 7, I'm estimating 7 point something.