Creating pie graphs

It is important that students understand the part-whole relationship that exists when creating a pie chart.

A circle, or pie, represents the whole of the data set (population or sample) that is the focus of discussion.

Usually the segments of a pie graph are labelled in percentages adding to 100% but fractions can be used.

The segments of a pie graph can be marked using a protractor and the percentage of 360 degrees that makes up the segment. However, it is also possible to create a pie graph with concrete materials. With small data sets and frequency data for each category, each value in the same category can be placed along a strip of paper in equal intervals.

Frequencies for categories.
Source: © Jane Watson.

The strip of paper is then rolled into a circle. Draw lines to connect the middle of the circle with the boundaries of the categories to create the pie graph.

Pie graph created from the frequencies.
Source: © Jane Watson.