Constructing pie charts

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

Constructing pie charts using a table


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

Table showing the grades achieved by 30 pupils in their end-of-year exam

To present this information on a pie chart, use the following steps:

  1. Work out the total number of pupils: 7 + 11 + 6 + 4 + 2 = 30
  2. To calculate the angle of each segment, work out the fraction of the total that got each grade. Start with A grades: \frac{7}{30}
  3. There are 360^\circ in a full turn. So to work out the angle, multiply the fraction by 360: \frac{7}{30} \times 360 = 84^\circ
  4. Repeat this process to find the angles for the other segments. Check that the angles are correct by seeing if they add to 360^\circ.
  5. Once you have calculated the angles of the segments, construct the pie chart.

Complete the following table. You could then use the data to construct a pie chart.

Table to construct a pie chart showing Grade, Frequency and Age
Completed table showing data for Grade, Frequency and Age to construct a pie chart