Pie charts

​​In a nutshell

A pie chart shows things as proportions. The size of each sector of the circle tells you how big the proportion is and can be written as a percentage, a fraction or in degrees.

​

Reading pie charts

​Each shaded part of the circle is a sector. There are 360° in a circle and so each sector has an angle which is a fraction or percentage of 360.​

Example

​The pie chart represents modes of transport taken to school by 20 students. How many students walk?​

The angle at the centre of the walking sector is $$90\degree$$. Work out this as a fraction of $$360\degree$$.​

$$90$$ is $$\frac{1}{4}$$​​ of $$360$$

​

Work out a quarter of the total number of students: $$20.$$

​​

$$\frac{1}{4}$$​ of $$20$$ is $$5$$

​​

Five students walk to school.

Drawing pie charts

​​PROCEDURE