1. Statistics and Probability
Chapter 7
Statistics and Probability

2. 7.2
Reading Circle Graphs

3. Example Find the ratio of baseball players to basketball players.
Objective A 3

4. Example
The following graph shows the percent of visitors to the U.S. in a recent year by various regions. Use the circle graph to determine the percent of visitors who came to the U.S. from Mexico and Canada.
Objective A
12.3% % = 49.8% 4

5. Example
The U.S. Department of Commerce forecasts 61,000,000 international visitors to the U.S. in Estimate the number of tourist that might be from Europe.
amount = percent · base
Objective A
amount = 0.20 · 61,000,000
= 0.20(61,000,000)
= 12,200,000 5

6. Example
The following table shows the percentage of U.S. armed force personnel that were in each branch of service in (Source: U.S. Department of Defense) Draw a circle graph showing this data.
Branch of Service
Percent
Army 38
Navy 23
Marine Corps 14
Air Force 22
Coast Guard 3
Objective A
continued 6

7. continued First we find the number of degrees in each sector. Sector
Army
Navy
Marine Corps
Air Force
Coast Guard
Objective A
continued 7

8. continued
Next we draw a circle, mark its center and draw a line from the center to the circle itself. We then use a protractor to construct the sections. A protractor measures the number of degrees in an angle. It makes no difference which sector you draw first.
Objective A
continued 8

9. continued
To construct the “Navy” sector, we follow the same procedure, except we line up 0 degrees with the second line.
Objective A
continued 9

10. continued
We continue until the graph is complete.
Objective A 10