January 28, 2015
Lesson 4.6: Interpreting Circle Graphs
Objective: Construct, label, and interpret circle graphs to
solve problems
Get Started: p. 156
Let's list some of our favorite after-school activities... Then we will
vote on our favorite.
Hanging out with friends, napping, playing video games,
playing sports, reading
What are some different ways we could display this data?
bar graph, picture graph, circle graph
Explore p. 156:
DO TOGETHER:
Look at the circle graph found on page 156.
What activity is the:
Most popular? Hanging out with Friends
Least popular? Reading
How do you know?
Most popular:
Least popular:
largest piece & highest %
smallest piece & smallest %
Which two activities are equally popular?
Doing Homework & Watching TV
How do you know?
They have the same-sized piece and they each represent 10%
of the student population
How many students prefer hanging out with friends?
30% = 0.30 ----> 0.30 x 60 = 18 students
January 28, 2015
How many students prefer:
(put the percentage and # of students)
playing video games?
25% = 0.25, 0.25 x 60 = 15 students
doing homework?
10% = 0.10, 0.10 x 60 = 6 students
reading?
5 % = 0.05, 0.05 x 60 = 3 students
watching TV?
10% = 0.10, 0.10 x 60 = 6 students
playing sports?
20% = 0.20, 0.20 x 60 = 12 students
page 156. cont...
Which activity is preferred by about one-third of the students?
Why do you think so?
Hanging out with Friends.
Since 1/3 = 0.3333333..., which is 33.3 %.
30% is the closest to 33%.
What else do you know from looking at the graph?
- playing video games is 1/4 of the students (25%)
- same # of students prefer watching TV & doing homework
- # of students who prefer playing video games is equal to the #
of students who prefer watching tv, reading and doing homework.
January 28, 2015
Connect
What do you notice about the sum of the percents?
They add up to 100%
What do you notice about the sum of the numbers of students who prefer
each activity?
They add up to 60 students (total # of students surveyed)
What can you not tell from looking at the graph?
- How many grade 7 students there are
- you can only tell this by reading the question
Characteristics of a Circle Graph:
There must be a title.
Each sector must be labeled with a heading and a percent.
Characteristics of a Circle Graph:
There must be a title.
Each sector must be labeled with a heading and a percent.
TITLE
HEADING
PERCENT
HEADING
PERCENT
HEADING
PERCENT
HEADING
PERCENT
HEADING
PERCENT
January 28, 2015
Examples:
1.
Luge
Speed Skating
20%
Hockey
20%
This circle graph shows the Olympic Sports that
Mr. Ducharme watched on TV.
Alpine 15%
Skiing
Figure Skating
30%
a) What percent of the time did Mr. Ducharme watch Luge?
The total circle graph represents 100%.
The sum of the given %'s are 20 + 20 + 15 + 30 = 85%. The
remaining percent is 15%.
b) If Mr. Ducharme spent 24 hours watching the Olympics on TV,
how much time was spent watching each sport?
Luge:
15% = 0.15, 0.15 x 24 = 3.6 hours
Speed Skating:
20% = 0.20, 0.20 x 24 = 4.8 hours
Figure Skating:
30% = 0.30, 0.30 x 24 = 7.2 hours
Alpine Skiing:
15% = 0.15, 0.15 x 24 = 3.6 hours
Hockey:
20% = 0.20, 0.20 x 24 = 4.8 hours
Homework: p. 158 # 1, 2, & 5 (AFQ)
Luge
Hockey
20%
Speed Skating
20%
Alpine 15%
Skiing
Figure Skating
30%