Pie charts
Pie charts are drawn as a circle representing all the data given. The 360 degrees about the centre of the circle is divided up according to the proportions of the different quantities shown.
Example
The following table shows where a group of pupils went for their summer holidays.The results are given as percentages and need to be converted into degrees to be measured out and drawn as a pie chart.
| Destination | Percentage of pupils (%) | Calculation | Angle |
| Spain | 40 | \(\frac{40}{100} \times 360^\circ\) | \(144^\circ\) |
| America | 25 | \(\frac{25}{100} \times 360^\circ\) | \(90^\circ\) |
| France | 5 | \(\frac{5}{100} \times 360^\circ\) | \(18^\circ\) |
| Scotland | 20 | \(\frac{20}{100} \times 360^\circ\) | \(72^\circ\) |
| Greece | 10 | \(\frac{10}{100} \times 360^\circ\) | \(36^\circ\) |
| Destination | Spain |
|---|---|
| Percentage of pupils (%) | 40 |
| Calculation | \(\frac{40}{100} \times 360^\circ\) |
| Angle | \(144^\circ\) |
| Destination | America |
|---|---|
| Percentage of pupils (%) | 25 |
| Calculation | \(\frac{25}{100} \times 360^\circ\) |
| Angle | \(90^\circ\) |
| Destination | France |
|---|---|
| Percentage of pupils (%) | 5 |
| Calculation | \(\frac{5}{100} \times 360^\circ\) |
| Angle | \(18^\circ\) |
| Destination | Scotland |
|---|---|
| Percentage of pupils (%) | 20 |
| Calculation | \(\frac{20}{100} \times 360^\circ\) |
| Angle | \(72^\circ\) |
| Destination | Greece |
|---|---|
| Percentage of pupils (%) | 10 |
| Calculation | \(\frac{10}{100} \times 360^\circ\) |
| Angle | \(36^\circ\) |
The pie chart will therefore look like this.
Question
A class of pupils were asked to toss coins. The results were 13 heads and 17 tails.
Show this information in a pie chart
Since there are 30 results, divide 360 by 30, so each result is worth 12 degrees.
Heads \(= 13 \times 12 = 156^{\circ}\)
Tails \(= 17 \times 12 = 204^{\circ}\)
