Home Back to the Challenge Try These Think About This... Did You Know? Resources Try Another Challenge
Answer
Figure This!
 

Quick Answer:
The process described in the Hint shows that the shorter cylinder holds more.

 

 

Complete Solution:
To determine an answer mathematically, find the volume of each cylinder. The volume is the area of the base times the height. In this case, the bases are circular.

The area of a circle is × r × r or approximately 3.14 × r × r. To find the radius, r, use a ruler to estimate the width (or diameter) of the circle. Divide the diameter by 2 to get the radius.

Another way to find the radius of a circle is to use the formula:

Circumference = 2 × × radius = 2r.
Radius = Circumference ÷ (2 ).

Once you have the radius, the table below shows how to determine the volume of each cylinder. The sheet of paper is 8 1/2 inches by 11 inches.

The volume of the shorter cylinder is about 82 cubic inches, and the volume of the taller cylinder is about 63 cubic inches.

 
       
Cylinder

Base
Circumference (inches)

Radius
r
(inches)

Height
h (inches)

Volume
× r × r × h
(Cubic Inches)

Short
11
11÷(2) or about 1.75
8.5

×1.75 × 1.75 × 8.5
about 81.8

Tall
8 1/2 = 8.5
8.5÷(2) or about 1.35
11
×1.35 × 1.35 × 11
about 63.0
 
Home · Back to the Challenge · Try These · Think About This  ·  Did You Know? · Resources
Try Another Challenge · Challenge Index · Math Index · Printing the Challenges · En Español
Family Corner · Teacher Corner · About Figure This! · Purchase the CD
©2004 National Council of Teachers of Mathematics
Web site and CD-ROM design/production
© 1999-2004 KnowNet Construction, Inc.