year 8 maths

546 Chapter 9 Data collection, representation and analysis
Example 7 Drawing a sector graph and a divided bar graph
On a particular Saturday, Sanjay measured the number of hours he spent on different activities.
TV internet sport homework
1 hour 2 hours 4 hours 3 hours
Represent the table as:
a a sector graph b a divided bar graph
SOLUTION
a
TV
homework
internet
sport
EXPLANATION
The total amount of time is
1 + 2 + 4 + 3 = 10 hours. Then we can calculate
the proportions and sector sizes:
Category Proportion Sector size ( ° )
TV 1
10 = 0.1 = 10% 1
× 360 = 36
10
internet 2
10 = 0.1 = 20% 2
× 360 = 72
10
sport 4
10 = 0.4 = 40% 4
× 360 = 144
10
homework 3
10 = 0.3 = 30% 3
× 360 = 108
10
b
TV internet
0.0 0.1 0.2 0.3
sport homework
Using the same proportions calculated above,
make sure that each rectangle takes up the correct
0.4 0.5 0.6 0.7 0.8 0.9 1.0 amount of space. For example, if the total width is
15 cm , then sport occupies 2 5 × 15 = 6 cm . .
Exercise 9D
UNDERSTANDING AND FLUENCY
1–4 2–5
3–5
1 Jasna graphs a sector graph of how she spends her leisure time.
a What does Jasna spend the most time doing?
b What does Jasna spend the least time doing?
c Does she spend more or less than half of her time
playing sport?
internet
TV
homework
sport
Cambridge Maths NSW
Stage 4 Year 8 Second edition
ISBN 978-1-108-46627-1 © Palmer et al. 2018
Cambridge University Press
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