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Maths

Representing data

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Constructing pie charts

To construct a pie chart you need to work out the fraction of the total that the sector represents. You can then convert this to an angle and draw the sector on the chart.

Constructing pie charts - using a table

Example

The table below shows the grades achieved by 30 pupils in their end-of-year exam.

Grade A B C D E
Frequency 7 11 6 4 2

To show this information in a pie chart, take the following steps:

  1. Work out the total number of pupils: 7 + 11 + 6 + 4 + 2 = 30

  2. To work out the angle of each segment, work out the fraction of the total that got each grade.

    Start with A grades: 7 /30

  3. There are 360° in a full turn, so to work out the angle, multiply the fraction by 360: 7 /30 × 360 = 84°

    The grade A sector has an angle of 84°

  4. Repeat this process to find the angle of the segments for the other grades
  5. Once you have calculated the angles of the segments, construct the pie chart
Question

Copy and complete the following table, then use the data to construct a pie chart.

Grade Frequency Angle
A 7

7 /30 × 360 = 84°

B 11  
C 6  
D 4  
E 2  
Answer

Grade Frequency Angle
A 7

7/30 × 360 = 84°

B 11

11 /30 × 360 = 132°

C 6

6 /30 × 360 = 72°

D 4

4 /30 × 360 = 48°

E 2

2 /30 × 360 =24°

Activity

Representing data activity

Fancy some pie? Try this activity.

Play

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