Pie charts should be ... the visual attributes of the charts, e.g., red wedge, blue lines, etc., unless there is an explicit need such as an exam question referring to these attributes. It is helpful ...

When drawing a pie chart ... the pupils whose favourite hobby is playing video games is 20% of the pie chart. Number of pupils = 20% of 660 = 0.20 × 660 = 132. One hundred and thirty-two students ...