around the house for six objects that are circular, or have a circular part,
such as a cylinder. Try to find a variety of sizes of circles.
Illustrate each object. Measure
the circumference and diameter of the circular part and label them in the
To find the circumference you could
a flexible ruler that is used for sewing.
a string around the circumference and then measure the length of the string.
in the table with the diameter and circumference of your object. Then find the
ratio of the circumference to the diameter.
All the ratios of the
circumference to the diameter should be close to the same number. If not,
double check your measurements. What special number is equal to the ratio
of the circumference to the diameter?
Do you think that this ratio is
the same if the circles are measured in miles rather than centimeters or