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Using/drawing Pie Charts
A Brief Explanation of how to use Pie Charts, particularly at GCSE Level
Date : 13/06/2022
Pie Charts are used to quickly represent the Proportions of each Group of Data.
We do this by taking `Slices` of a Circle, that are proportional towards the size of each group. For instance, in the chart below (showing Proportions of Native English speakers across the world), we give a Larger `Slice` to the USA since this is the country with the greatest amount of native English speakers. We also give a Larger `Slice` to the UK, compared to Canada and Australia.
The Proportion of each `Slice` will also be equal to the ;Central Angle (Angle at Centre) of the `Slice`, divided by 360 Degrees. This is since within a Circle, the Sum of Angles are always 360 Degrees. Thus by dividing the Central Angle by this, we are thus dividing the Angle of ONE `Slice` by the Angle of ALL the Slices, within the Pie Chart.
Knowing these two things, we should be able to Construct Pie Charts given a Table of Data. An Example is shown below:
Comedy. Action. Romance. ;Drama. Sci-Fi. Total
4 5 6 1 4. 20
1). Looking at the table above, we first need to find the proportions of each Group of Data
-Comedy: 4/20 (4/Total)
-Action: 5/20 (5/Total)
-Romance: 6/20 (6/Total)
-Drama: 1/20 (1/Total)
-Sci-Fi: 4/20 (4/Total)
2). The Proportions will tell us the Proportion of Each `Slice` of the Pie Chart. We can use these Same Proportions to find the Central Angle of each `Slice`.
-Comedy: 4/20 x 360 = 72
-Action: 5/20 x 360 = 90
-Romance: 6/20 x 360 = 108
-Drama: 1/20 x 360 = 18
-Sci-Fi: 4/20 x 360 = 72
3). We can then use a Protractor to Draw each of these Slices with these Central Angles. This will allow us to Complete our Construction of a Pie Chart
Have a go at the Example shown below:
A Group of students perform a Maths Test. They produce the following Data. Draw a Pie Chart to Represent this.
A. ; B. ; C. ; D.
4. ; 10 ; 12. ;2
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