Geometry

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# Surface Area of a Cube

## Cube Surface Area Formula

The formula for surface area of a cube is given as:**SA = 6a ^{2}**

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 = a^{2}).

### 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 = 6a^{2}

3.) SA = 6(8^{2}) = 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 = 6a^{2}

3.) 864 = 6a^{2}

4.) 144 = a^{2}

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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