Drawing pie charts Use the worked example below to help you draw pie charts.
Sample Question: Draw a pie chart to represent the data in the table shown below. This table shows the shape of 15 stones sampled at Site 1 of the Whitewater River, County Down.
Stone No. 1 2 3 4 5 6 7 8
Shape Angular
Sub-rounded Sub-rounded Angular
Very angular Angular Angular Angular
Stone No. 9
10 11 12 13 14 15
Pie Chart to show the shape of 15 stones from Site 1, Whitewater River
Shape
Very angular Sub-angular Angular
Sub-rounded Angular Angular
Sub-rounded
Very angular 13%
Sub-rounded 27%
Sub-angular 7%
Angular 53%
KEY KEY
Very angular Angular Sub-angular Sub-rounded
Answer: 15 stones must be shared out amongst 360 degrees of the pie. Therefore, each stone is: 360/15 = 24 degrees. Make a rough table to work out what size each segment of the pie will be.
Shape category Very angular Angular
Sub-angular Sub-rounded
No. of stones 2 8 1 4
Portion of the pie chart (degrees) 2 x 24 = 48 degrees 8 x 24 = 192 degrees 1 x 24 = 24 degrees 4 x 24 = 96 degrees
To draw the pie, you must use a compass, protractor and graph paper. Mark the centre of the circle clearly as marks are given for neatness and accuracy. Start by drawing a horizontal line from the centre to the left edge of the pie using
your protractor. Draw all segments from this line in a clockwise direction. Label or use colours to show all the pie segments. Provide a key and title.
Pie Chart Exercise Draw a pie chart to represent the data in the table below: Traffic survey: vehicles per hour passing along Mary Street, Dublin City.