Drawing a pie chart
Look at this record of traffic travelling down a particular road.
| Type of vehicle | Number of vehicles |
| Cars | \(140\) |
| Motorbikes | \(70\) |
| Vans | \(55\) |
| Buses | \(5\) |
| Total vehicles | \(270\) |
| Type of vehicle | Cars |
|---|---|
| Number of vehicles | \(140\) |
| Type of vehicle | Motorbikes |
|---|---|
| Number of vehicles | \(70\) |
| Type of vehicle | Vans |
|---|---|
| Number of vehicles | \(55\) |
| Type of vehicle | Buses |
|---|---|
| Number of vehicles | \(5\) |
| Type of vehicle | Total vehicles |
|---|---|
| Number of vehicles | \(270\) |
To draw a pie chart, we need to represent each part of the data as a proportion of 360, because there are \(360^{\circ}\) in a circle.
For example, if 55 out of 270 vehicles are vans, we will represent this on the circle as a segment with an angle of: \(\frac{{55}}{{270}} \times 360 = 73\) degrees.
This will give the following results:
| Type of vehicle | Number of vehicles | Calculation | Degrees |
| Cars | \(140\) | \(\frac{{140}}{{270}} \times 360\) | \(187^{\circ}\) |
| Motorbikes | \(70\) | \(\frac{{70}}{{270}} \times 360\) | \(93^{\circ}\) |
| Vans | \(55\) | \(\frac{{55}}{{270}} \times 360\) | \(73^{\circ}\) |
| Buses | \(5\) | \(\frac{{5}}{{270}} \times 360\) | \(7^{\circ}\) |
| Type of vehicle | Cars |
|---|---|
| Number of vehicles | \(140\) |
| Calculation | \(\frac{{140}}{{270}} \times 360\) |
| Degrees | \(187^{\circ}\) |
| Type of vehicle | Motorbikes |
|---|---|
| Number of vehicles | \(70\) |
| Calculation | \(\frac{{70}}{{270}} \times 360\) |
| Degrees | \(93^{\circ}\) |
| Type of vehicle | Vans |
|---|---|
| Number of vehicles | \(55\) |
| Calculation | \(\frac{{55}}{{270}} \times 360\) |
| Degrees | \(73^{\circ}\) |
| Type of vehicle | Buses |
|---|---|
| Number of vehicles | \(5\) |
| Calculation | \(\frac{{5}}{{270}} \times 360\) |
| Degrees | \(7^{\circ}\) |
This data is represented on the pie chart below.
Question
Ninety people were asked which newspaper they read.
45 read the Daily Bugle.
20 read England Today.
15 read another paper.
10 do not read a paper.
Calculate the number of degrees required to represent each answer in a pie chart.
| Newspaper | Number of people | Calculation | Degrees |
| The Daily Bugle | \(45\) | \(\frac{{45}}{{90}} \times 360\) | \(180^{\circ}\) |
| England Today | \(20\) | \(\frac{{20}}{{90}} \times 360\) | \(80^{\circ}\) |
| Other | \(15\) | \(\frac{{15}}{{90}} \times 360\) | \(60^{\circ}\) |
| I do not read a paper | \(10\) | \(\frac{{10}}{{90}} \times 360\) | \(40^{\circ}\) |
| Newspaper | The Daily Bugle |
|---|---|
| Number of people | \(45\) |
| Calculation | \(\frac{{45}}{{90}} \times 360\) |
| Degrees | \(180^{\circ}\) |
| Newspaper | England Today |
|---|---|
| Number of people | \(20\) |
| Calculation | \(\frac{{20}}{{90}} \times 360\) |
| Degrees | \(80^{\circ}\) |
| Newspaper | Other |
|---|---|
| Number of people | \(15\) |
| Calculation | \(\frac{{15}}{{90}} \times 360\) |
| Degrees | \(60^{\circ}\) |
| Newspaper | I do not read a paper |
|---|---|
| Number of people | \(10\) |
| Calculation | \(\frac{{10}}{{90}} \times 360\) |
| Degrees | \(40^{\circ}\) |
This pie chart is drawn stage by stage below.
Before you draw the pie chart, remember to check that the angles which you have calculated add up to \(360^{\circ}\).
The outline of a circle
A circle with a radius line going vertically up from the centre
A circle divided up into sectors of varying angles
A pie chart showing how many people read various newspapers