Geometry

Surface Area of a Cube

Cube Surface Area Formula

The formula for surface area of a cube is given as:
SA = 6a2
Where SA is the surface area, and a is the edge length.

A cube has 6 faces that are all squares. The surface area formula is 6 times the area of a square (area of a square = a2).

surface area of a cube

Example Problems

Problem 1:
Find the surface area of a cube with an edge length of 8.
Solution:
1.) Let’s plug the edge length into the formula.
2.) SA = 6a2
3.) SA = 6(82) = 384
4.) The surface area of the cube is 384.

Problem 2:
What is the edge length of a cube with a surface area of 864?
Solution:
1.) Let’s plug the surface area into the surface area formula and then solve for the edge length a.
2.) SA = 6a2
3.) 864 = 6a2
4.) 144 = a2
5.) a = √144
6.) a = 12
7.) The edge length is 12.

Result :

Worksheet 1

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Cheat sheet

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