Pie charts
A pie chart shows the frequency of each category as a sector of a circle. There are 360° in a circle, so each category will be represented in the pie chart as a proportion of 360°.
Example
A survey of the number of people travelling in a vehicle is taken.
The results are summarised in the table below.
| People travelling in a vehicle | Frequency |
| 1 person | 120 |
| 2 people | 40 |
| 3 people | 13 |
| 4 people | 5 |
| 5 or more | 2 |
| Total | 180 |
| People travelling in a vehicle | 1 person |
|---|---|
| Frequency | 120 |
| People travelling in a vehicle | 2 people |
|---|---|
| Frequency | 40 |
| People travelling in a vehicle | 3 people |
|---|---|
| Frequency | 13 |
| People travelling in a vehicle | 4 people |
|---|---|
| Frequency | 5 |
| People travelling in a vehicle | 5 or more |
|---|---|
| Frequency | 2 |
| People travelling in a vehicle | Total |
|---|---|
| Frequency | 180 |
To draw a pie chart for this data, work out each proportion of 360°.
| People travelling in a vehicle | Frequency | Calculation | Angle |
| 1 person | 120 | \(\frac{120}{180} \times 360°\) | 240° |
| 2 people | 40 | \(\frac{40}{180} \times 360°\) | 80° |
| 3 people | 13 | \(\frac{13}{180} \times 360°\) | 26° |
| 4 people | 5 | \(\frac{5}{180} \times 360°\) | 10° |
| 5 or more | 2 | \(\frac{2}{180} \times 360°\) | 4° |
| Total | 180 |
| People travelling in a vehicle | 1 person |
|---|---|
| Frequency | 120 |
| Calculation | \(\frac{120}{180} \times 360°\) |
| Angle | 240° |
| People travelling in a vehicle | 2 people |
|---|---|
| Frequency | 40 |
| Calculation | \(\frac{40}{180} \times 360°\) |
| Angle | 80° |
| People travelling in a vehicle | 3 people |
|---|---|
| Frequency | 13 |
| Calculation | \(\frac{13}{180} \times 360°\) |
| Angle | 26° |
| People travelling in a vehicle | 4 people |
|---|---|
| Frequency | 5 |
| Calculation | \(\frac{5}{180} \times 360°\) |
| Angle | 10° |
| People travelling in a vehicle | 5 or more |
|---|---|
| Frequency | 2 |
| Calculation | \(\frac{2}{180} \times 360°\) |
| Angle | 4° |
| People travelling in a vehicle | Total |
|---|---|
| Frequency | 180 |
| Calculation | |
| Angle |
