Question

What is the length of each edge of a cube if its surface area is 486 square units?

Answer 1

SA = 2LW + 2LH + 2WH
Since it is a cube, all of the dimensions, LWH, will be the same.
SA = 2s^2 + 2s^2 + 2s^2
SA = 6s^2
486 = 6s^2
Divide both sides by 6
81 = s^2
Take the square root of both sides.
9 = s

Answer 2

9

Explanation:

find the surface area : SA = 2LW + 2LH + 2WH

This is a cube, so the length, width and height will be the same

SA = 2s^2 + 2s^2 + 2s^2

SA = 6s^2

486 = 6s^2

486/6 = 6s^2/6

81 = s^2

Take the square root of both sides.

9 = s