Answer: 6 inches
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Explanation:
A cube is made up of 6 square faces. For now, focus on one square only. Let's say that square has a side length of x. So the area of that square is x*x = x^2. Since there are 6 faces, this means there is a total surface area of 6x^2
So,
SA = 6x^2
Replace the "SA" with 216 since we know the surface area. Then solve for x
216 = 6x^2
6x^2 = 216
x^2 = 216/6 .... divide both sides by 6
x^2 = 36
x = sqrt(36)
x = 6
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If each square has a side length of x = 6 inches, then each square has an area of x^2 = 6^2 = 36 square inches. Then we multiply by 6 to get a total surface area of 6*36 = 216 square inches. This confirms the answer. You can use the formula to confirm the answer as well.
SA = 6x^2
SA = 6*6^2
SA = 6*36
SA = 216
