### All GRE Math Resources

## Example Questions

### Example Question #1 : How To Find The Surface Area Of A Sphere

Find the surface area of a sphere with a diameter of 14. Use *π* = 22/7.

**Possible Answers:**

2464

1256

428

616

872

**Correct answer:**

616

Surface Area = 4*πr*^{2} = 4 * 22/7 * 7^{2} = 616

### Example Question #2 : How To Find The Surface Area Of A Sphere

A sphere has a surface area of square inches. If the radius is doubled, what is the surface area of the larger sphere?

**Possible Answers:**

Cannot be determined

**Correct answer:**

The surface area of the larger sphere is NOT merely doubled from the smaller sphere, so we cannot double to find the answer.

We can use the surface area formula to find the radius of the original sphere.

*r*^{2} = 4

*r* = 2

Therefore the larger sphere has a radius of 2 * 2 = 4.

The new surface area is then square inches.

### Example Question #1 : How To Find The Surface Area Of A Sphere

If a sphere has a volume of cubic inches, what is its surface area?

**Possible Answers:**

**Correct answer:**

The volume of a cube is equal to .

So we mutiply our volume by and divide by , giving us .

The surface area of a sphere is equal to , giving us .