The area of one face would he h^2.
There are 6 faces, so the total surface area would be h^2 x 6
Replace total surface area with 2.16, so you now have:
2.16 = h^2 x 6
Now we can solve for h.
Divide both sides by 6:
h^2 = 2.16/6
Take the square root of both sides:
h = √2.16/6
The answer is A.
