# GED Math : Faces and Surface Area

## Example Questions

### Example Question #131 : 3 Dimensional Geometry

Find the surface area of a cube with a length of 12in.

Explanation:

To find the surface area of a cube, we will use the following formula:

where l is the length, and w is the width of the cube.

Now, we know the length of the cube is 12in. Because it is a cube, all sides are equal. Therefore, the width is also 12in. So, we can substitute. We get

### Example Question #11 : Faces And Surface Area

A cube has a height of 8cm. Find the surface area.

Explanation:

To find the surface area of a cube, we will use the following formula:

where l is the length, and w is the width of the cube.

Now, we know the height of the cube is 8cm. Because it is a cube, all lengths, widths, and heights are the same. Therefore, the length and the width are also 8cm.

Knowing this, we can substitute into the formula. We get

### Example Question #131 : 3 Dimensional Geometry

A sphere has a radius of 5in. Find the surface area.

Explanation:

To find the surface area of a sphere, we will use the following formula:

where r is the radius of the sphere.

Now, we know the radius of the sphere is 5in.

So, we can substitute into the formula. We get

### Example Question #12 : Faces And Surface Area

Find the surface area of a cube with a height of 13in.

Explanation:

To find the surface area of a cube, we will use the following formula:

where l is the length, and w is the width of the cube.

Now, we know the length of the cube is 13in. Because it is a cube, all sides are equal. Therefore, the width is also 13in. So, we can substitute. We get

### Example Question #13 : Faces And Surface Area

Find the surface area of a sphere with a radius of 8in.

Explanation:

To find the surface area of a sphere, we will use the following formula:

where r is the radius of the sphere.

Now, we know the radius of the sphere is 8in.

Knowing this, we can substitute into the formula. We get

### Example Question #1653 : Ged Math

Give the surface area of the above sphere.

Explanation:

Given the radius  of a sphere, the surface area  can be calculated using the formula

.

Set  in the formula and evaluate:

### Example Question #141 : 3 Dimensional Geometry

A cube has a width of 8in. Find the surface area.

Explanation:

To find the surface area of a cube, we will use the following formula:

where l is the length, and w is the width of the cube.

Now, we know the width of the cube is 8in. Because it is a cube, all sides/lengths are equal. Therefore, the length is also 8in. So, we can substitute. We get

### Example Question #141 : 3 Dimensional Geometry

Let

Find the surface area of a sphere with a radius of 5in.

Explanation:

To find the surface area of a sphere, we will use the following formula:

where r is the radius of the sphere.

Now, we know . We know the radius of the sphere is 5in. So, we can substitute. We get

### Example Question #691 : Geometry And Graphs

Let

If a sphere has a radius of 3cm, find the surface area.

Explanation:

To find the surface area of a sphere, we will use the following formula:

where r is the radius of the sphere.

Now, we know . We know the radius of the sphere is 3cm. So, we substitute. We get

### Example Question #11 : Faces And Surface Area

Find the surface area of a cube with a length of 9in.