A pie chart is used to show percentages of a whole. Below is a pie chart showing Isla’s expenditure divided into Fixed, Irregular and Discretionary. How to construct a pie chart:
1. Collect data: data collected should be accurate and carefully collected. 2. Calculate the proportions:
Using a pencil, draw a circle. From the centre of the circle, divide it into segments with a ruler.
The various proportions are calculated as follows:
€160 = 100% Fixed expenditure = €10 10
160 × ×
100 1
100 1
Isla’s Planned Expenditure = 6.25%
Irregular expenditure = €100 100 160
160 ×
100 1
= 62.5%
Discretionary spending = €50 50
= 31.25%
Analysing the pie chart: We can see from the pie chart that Isla’s fixed expenditure was 6%. Irregular expenditure was the largest expenditure at 63% and discretionary expenditure was 31%.
Fixed expenditure
Irregular expenditure
6% 31% 63%
Discretionary expenditure
1. Create a bar chart for the Kellys’ income for January, February and March (see page 31).
Write It!
2. Create a line graph showing the Kellys’ closing cash for January, February and March (see page 31).
3. Create a pie chart for the Kellys’ total expenditure for the three months, showing fixed, irregular and discretionary spending (see page 31).
Tips foR Success
Presenting data in a graph: Always have a title.
Use clear labels.
Make sure the graph/ chart is accurate.
34 P. 16
Go to page 16 in the activity book to practise constructing graphs.