3. Use a compass to draw a suitably-sized circle, and then use a protractor to mark out the degree segments for each category. Remember to shift the protractor to zero again after each segment!
4. Label each segment with the percentage data. 5. Colour or shade the separate segments as appropriate.
Example
Pie chart = 360° = 100%
The table below shows the proportions of energy consumed by different sectors in Ireland. Type
To convert degrees into a percentage, divide by 3.6.
For example, 54°: 54 ÷ 3.6 = 15%
To convert a percentage into degrees, multiply by 3.6.
For example, 90%: 90 × 3.6 = 324°
Transport
Residential Industry Services
Agriculture Fig. 15.3 Constructing a pie chart. 2% 14%
% 41 27 16 14 2
× 3.6 =
Degrees 148 58 97 50 7
To display the data in a pie chart format, the percentages must be converted to degrees. You multiply the value for each sector by 3.6 to give the number of degrees it will need on the pie chart.
The different values/sectors can then be transferred onto a circle to create a pie chart. (Fig. 15.4)
SKILLS ACTIVITY 16% 41% Construct a pie chart to illustrate the data in this table.
Overseas Visitors to Ireland 2016 Source Area
Great Britain 27% Transport Residential Services Industry Agriculture Fig. 15.4 Sample pie chart. 1.5% 2005 12.9% 10.8% 72.7%
Kerry Knock Shannon Cork
Dublin 2.1% 2013 1.2%
5.3% 2.7%
9.1%
Mainland Europe North America Rest of World
% 42 35 17 6
81.7%
Fig. 15.5 Percentage share of total passengers for Irish airports 2005 and 2013. 230
