SEARCH HOME
Math CentralQuandaries & Queries

search

Question from Hannah, a student:

If the volume of a cone of height 10 cm is 261.8 cm3, show that this
volume is increased by a factor of 8 if the dimensions of the cone are doubled.

Hi Hannah,

I don't like this problem. The numbers given, 10 centimeters and 261.8 cubic centimeters just confuse the issue.

The volume of a cone is given by

\[\mbox{volume } = \frac13 \times \pi \; \mbox{(the radius of the base)}^2 \times \mbox{(the height).}\]

Suppose you have a cone with the radius of the base $r$ centimeters and the height $h$ centimeters. Write the expression for its volume.

Suppose you have a cone with the radius of the base $2r$ centimeters and the height $2h$ centimeters. Write the expression for its volume. Simplify this expression to see it is 8 times the volume of the first cone.

Penny

About Math Central
 

 


Math Central is supported by the University of Regina and the Imperial Oil Foundation.
Quandaries & Queries page Home page University of Regina