### All GRE Math Resources

## Example Questions

### Example Question #9 : Solid Geometry

A cylinder has a height of 4 and a circumference of 16π. What is its volume

**Possible Answers:**

16π

128π

256π

none of these

64π

**Correct answer:**

256π

circumference = πd

d = 2r

volume of cylinder = πr^{2}h

r = 8, h = 4

volume = 256π

### Example Question #1 : How To Find The Volume Of A Cylinder

Rusty is considering making a cylindrical grain silo to store his crops. He has an area that is 6 feet long, 6 feet wide and 12 feet tall to build a cylinder in. What is the maximum volume of grain that he can store in this cylinder?

**Possible Answers:**

**Correct answer:**

The maximum cylindrical base can have a diameter of 6 and therefore a radius of 3. The formula for the volume of a cylinder is , which in this case is .

### Example Question #2 : How To Find The Volume Of A Cylinder

A cylinder with volume of and a radius of has its radius doubled. What is the volume of the new cylinder?

**Possible Answers:**

**Correct answer:**

To begin, you must solve for the height of the original cylinder. We know:

For our values, we know:

Now, divide both sides by :

So, if we have a new radius of , our volume will be: