Page 1 of 4
Circle Graphs
BEFORE
Now
WHY?
You made and interpreted bar
graphs and line graphs.
You’ll interpret circle graphs
and make predictions.
So you can predict costs, as in
Exs. 17–19.
In the Real World
Word Watch
circle graph, p. 88
Roller Coasters A group of teenagers
are asked what they think about roller
coasters. Their answers are shown in
the circle graph at the right. How many
of them think roller coasters are great?
Opinions of Roller Coasters
Not fun 7
OK 15
A circle graph is a graph that represents
data as parts of a circle. The entire circle
represents all of the data. You can make
conclusions about the data in a circle
graph based on the size of each section.
EXAMPLE
1
Great 78
Interpreting a Circle Graph
Use the circle graph above.
a. To find out how many of the teenagers think roller coasters are great,
find the data value in the section labeled “Great.”
ANSWER The number who think roller coasters are great is 78.
b. To find out how many of the teenagers do not think roller coasters
are great, add the values in the “OK” and the “Not fun” sections:
15 7 22.
ANSWER The number who do not think roller coasters are great is 22.
Your turn now
The circle graph shows how many people out of 100
prefer each of four types of space materials for a paperweight.
1. Which type of paperweight is least
popular?
2. How many of the people do
not prefer a meteor?
3. Is it reasonable to say that moon
rock is the most popular choice?
Explain.
88
Chapter 2
Measurement and Statistics
Paperweight Materials
Moon rock 45
Meteor 22
Asteroid 22
Man-made
satellite 11
Page 2 of 4
EXAMPLE
with
2
Using a Graph
Ice Cream The circle graph shows the
favorite ice cream flavors of 100 students.
About 300 students will attend an ice
cream party. Predict how many students
will ask for vanilla ice cream.
Reading
Writing down key facts
as you read a problem
can help you solve it.
In Example 2, you know:
100 students were
surveyed, 38 of them like
vanilla ice cream, and
300 students will be at
the party.
Vanilla
38
Chocolate
40
Strawberry
22
Solution
Find the relationship between the number of students surveyed and the
number of students who will attend the party: 100 3 300.
Multiply the number of students who prefer vanilla by 3 to predict the
number of students who will ask for vanilla at the party: 38 3 114.
ANSWER About 114 students will ask for vanilla ice cream at the party.
Your turn now
Use the circle graph in Example 2.
4. Predict the number of students who will ask for strawberry ice cream
at an ice cream party for 200 students.
INTERNET
Exercises
eWorkbook Plus
CLASSZONE.COM
More Practice, p. 709
Getting Ready to Practice
Vocabulary Which type of graph is best suited for the purpose?
1. comparing separate categories
A. circle graph
2. comparing part of a data set to the entire set
B. line graph
3. showing change over time
C. bar graph
Population The circle graph shows the
population of the United States, in
millions, in 2000.
4. Which age group was the smallest?
5. How can you tell from the graph
that about half the population
was under 35 years old?
U.S. Population by Age
55
59
0–14
60
15–24
39
45–54
38
35–44
48
Lesson 2.7
25–34
40
Circle Graphs
89
Page 3 of 4
Practice and Problem Solving
with
Homework
Example Exercises
1
6–11
2
12–19
Tell which section of the circle graph below fits the description.
6. It represents about half the data.
7. It represents the least data value.
8. It represents the greatest data value.
A
C
B
Online Resources
CLASSZONE.COM
• More Examples
• eTutorial Plus
Geography The circle graph shows the amount of Earth’s surface, in
millions of square kilometers, that is covered by each ocean.
9. Which ocean covers the least area?
10. Which ocean covers the greatest
area?
11. What is the total area of the five
oceans?
Areas of Oceans
Arctic 14
Southern 19
Atlantic 77
Pacific 156
Indian 69
Predict The circle graph shows the types of hits by Cal Ripken, Jr.,
in one season. In Exercises 12–15, predict the number of hits he
might have gotten in 4 seasons.
Baseball Hits
12. singles
13. doubles
14. triples
15. home runs
16. Predict the total number of hits
Cal Ripken, Jr., might have gotten
in 3 seasons.
Home runs 27
Triples 7
Doubles 37
Singles 124
Marine Mammals The circle graph shows the total amount of
money spent to feed the three types of mammals at an aquarium
for one year.
17. Predict how much money will be
spent to feed the sea otters for
four years.
18. There are 4 sea lions. About how
much does it cost to feed one sea
lion for one year?
19. There are 7 harbor seals. About how
much does it cost to feed one harbor
seal for one year?
90
Chapter 2
Measurement and Statistics
Yearly Food Costs
Sea lions
$10,000
Harbor seals
$13,300
Sea otters
$40,000
Page 4 of 4
Favorite Season A group of people voted for their favorite season.
The results are shown in the circle graph.
20. Use the data to make a bar graph.
Favorite Season
Spring
229
21. Which season got the most votes?
Which graph did you use to decide?
22. On which graph can you see that
Summer
116
Winter
36
spring and summer combined got
slightly more than half the votes?
Fall
248
Movies The graph shows the amounts 100 people paid to rent a movie.
23. How many people out of 300 would you
Movie Rental Cost
expect to pay $4 or less?
$3 25
24. Writing Explain how a bar graph of the
$2 10
$5 8
$4 57
data would be similar to the circle graph.
25. Challenge Is a line graph a good choice
to represent the data? Why or why not?
Mixed Review
Evaluate the expression. (Lesson 1.4)
28
26. 5
27. (8 3 7) 3
5 11 8 12
28. 4
29. Graph the point (0, 8) on a coordinate grid. (Lesson 2.6)
Basic Skills Find the quotient.
30. 255 5
31. 468 3
32. 1250 25
33. 4725 21
Test-Taking Practice
INTERNET
State Test Practice
CLASSZONE.COM
The circle graph shows students’ favorite school lunches.
34. Multiple Choice How many more
students chose hot lunches than
homemade lunches?
A. 10
B. 12
C. 14
value for the number of students who
chose the salad?
G. 99
H. 250
Hot
264
Homemade
252
D. 18
35. Multiple Choice Which is a possible
F. 22
Types of Lunches
Salad
?
Sandwich
465
I. 258
Lesson 2.7
Circle Graphs
91