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°. Work out this as a fraction of 360°.
90 is 41 of 360
Work out a quarter of the total number of students: 20.
41 of 20 is 5
Five students walk to school.
Drawing pie charts
PROCEDURE
1. | Work out the proportion for each category. |
2. | Draw each category with the correct proportion. |
3. | Label each sector with the correct category. |