Concept Byte: Circle Graphs

Use With Lesson 10-6

ACTIVITY

Circle graphs show data as percents or fractions of a whole. The total of the data must be 100% or 1. The measure of the central angle for a particular category of the data is proportional to the percent or fraction of the total that the category represents. The measures of the central angles in a circle graph have a total of 360. To find a central angle for a category of data, you multiply the percent or fraction that the category represents by 360.

Activity 1

The circle graph below shows the results of a time study in which participants recorded how they spent their time over a 24-h period.

1. What is the measure of the central angle that represents the time spent on each activity? Round to the nearest tenth where necessary.
   1. Sleep
   2. Food
   3. Work
   4. Errands
   5. Entertainment
   6. Other

To make a circle graph, use a compass to make the circle and use a protractor to measure the central angles.

Activity 2

The physical education department asked students which of three sports was their first choice to include in the spring physical education classes. The table below shows the results of the survey.

2. For a circle graph, what is the measure of the central angle for each sport?
3. Use the data to draw and label a circle graph.

Activity 3

A store that sells music CDs keeps track of their weekly sales for inventory purposes. The table below shows the sales for the first week in March.

4. What percent of the total is each type of music?
5. For a circle graph of the data, what is the measure of the central angle for each type of music?
6. Use the data to draw and label a circle graph.

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