The frustum of any pyramid is the part left over if you cut off the top. We are looking at the particular case of a cone (truncate means to just cut off, so a truncated cone, is a cone that has been cut!)

To find its volume, first find the volume for the cone, and then find the volume of the smaller cone that was removed. Subtract your second value from the first.

Recall: V = 1/3 x r2h

For example

Find the volume of the frustum

[picture missing]

The cone has a total height of 10cm with radius 4cm.
The frustum has a height of 6cm and the top has a radius of 2cm.
That means the smaller cone we cut off has a height of 4cm and radius of 2cm.

Cone: 1/3 x 16cm2 x 10cm = 53.33cm3
Smaller Cone: 1/3 x 4cm2 x 4cm = 5.33cm3
Frustum: 53.33
cm3 - 5.33cm3 = 48cm3

Nothing in this section yet. Why not help us get started?

Nothing in this section yet. Why not help us get started?

## Related Topics

Requires a knowledge of…

## Related Questions

• 1
Vote
4

### What is a coordinate grid?

By Ryan McGuire on the 10th of January, 2013

• 1
Vote
3

### What is the general form for a quadratic equation?

By Filsan on the 10th of January, 2013

• 1
Vote
2

### What does the graph of Y = x Linear look like?

By Filsan on the 10th of January, 2013

• 1
Vote
3

### What is the equation of a straight line graph?

By Filsan on the 10th of January, 2013

• 0
4

### How do I find 15% of a value?

By Verity Painter on the 8th of January, 2013

• 0
1

### What does write the terms of a sequence mean?

By Filsan on the 6th of December, 2012

• 0
1

### what is a data collection sheet?

By Lee Mansfield on the 11th of June, 2012

• 2
4