1. Reading and Interpreting Circle Graphs

2. Vocabulary Circle graph- also called a pie chart, shows how a set of data is divided into parts. The entire circle contains 100% of the data. Sector- slice of the circle that represents one part of the entire data set.

3. The circle graph compares the number of species in each group of echinoderms. Echinoderms are marine animals that live on the ocean floor.

4. Use the circle graph to answer the question. Additional Example 1A: Life Science Application Which group of echinoderms includes the fewest number of species? The sector for sea lilies and feather stars is the smallest, so this group includes the fewest number of species.

5. Use the circle graph to answer the question. Additional Example 1B: Life Science Application Approximately what percent of echinoderm species are brittle stars and basket stars? about, so approximately 33% 1313

6. The circle graph compares the sales of different types of cars during one year. Approximately what percent of cars were midsize? Check It Out: Example 1A

7. Leon surveyed 30 people about pet ownership. The circle graph shows his results. Use the graph to answer each question. Additional Example 2A: Interpreting Circle Graphs How many people own dogs only? The circle graph shows that 20% of the 30 people own dogs only. 20% of 30 = 0.2 30 = 6 6 people own dogs only.

8. Leon surveyed 30 people about whether they own pets. The circle graph shows his results. Use the graph to answer each question. Additional Example 2B: Interpreting Circle Graphs How many people own both cats and dogs? Since 20% is 6 people, 10% is 3 people. 3 people own both cats and dogs.

9. Check It Out: Example 2 Fifty students were asked which instrument they could play. The circle graph shows the responses. How many play the flute?

10. A company reports its annual charitable contributions. Draw a circle graph to represent this data. Additional Example 3: Drawing a Circle Graph Step 1: Find the total dollars contributed. 120,000 + 60,000 + 120,000 + 96,000 + 84,000 = 480,000

11. Additional Example 3 Continued Step 2: Find the percent each cause is to the whole. Education and Health EnvironmentDisaster Relief Arts & Humanties Step 3: Multiply the percent times 360 (the total number of degrees in a circle) for each contribution to find the measure of the central angle.

12. Additional Example 3 Continued Step 4: Use a protractor to draw each angle inside a circle. Label each wedge with the corresponding percent.

13. A group of track and field team members are asked which event is their favorite. Draw a circle graph to represent this data. Check It Out: Example 3 EventNumbers Sprints24 Hurdles18 Relay30 Jumping12 Throwing36