1. Handling Data Pie Charts Data (numbers) can be shown much more clearly using charts and graphs.

2. Handling Data Pie Charts One type of chart very frequently used is a pie chart.

3. Handling Data Pie Charts How do we draw a pie chart so that each sector (slice of pie) is the correct size to show the number? This is all based on dividing up the number of degrees in a circle (360 0 ) equally first.

4. Handling Data Pie Charts Lets start with some data. A tray of pencils contains the following colours: Colour of PencilNumber of Pencils Blue9 Red11 Green7 Yellow6 Orange3 Total36

5. Handling Data Pie Charts There are 36 pencils in total How should we divide up the 360 0 of a circle to represent all 36 pencils? If we said 1 0 represents 1 pencil, how many degrees would be used? 36

6. Handling Data Pie Charts 36 0 Only a small part of the whole circle is used.

7. Handling Data Pie Charts If we said 2 0 represents 1 pencil, how many degrees would be used? 36

8. Handling Data Pie Charts 72 0 A bit more of the circle is used, but still nowhere near the whole circle.

9. Handling Data Pie Charts We could keep on increasing the number of degrees represented by one pencil until the whole circle (360 0 ) is used… or we could Divide 360 0 by the 36 pencils. This will tell us that each pencil is represented by 10 0 !

10. Handling Data Pie Charts If each sector represents 1 pencil, to show the blue pencils we would need to colour in 9 of them blue.