When you collect and record data, you can represent it in a diagram. To show the results you can use a bar chart, pie chart, line graph, pictogram, frequency diagram or scatter diagram.

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.

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

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

- Work out the total number of pupils:
- To calculate the angle of each segment, work out the fraction of the total that got each grade. Start with A grades:
- There are in a full turn. So to work out the angle, multiply the fraction by :
- Repeat this process to find the angles for the other segments. Check that the angles are correct by seeing if they add to .
- Once you have calculated the angles of the segments, construct the pie chart.

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