GCSE Maths Revision. Made Easy
Maths - Pie charts - Everything you need to know!
Pie charts can be a great way to represent data and to more clearly show your findings. It’s important that you know how to draw one from previously gathered data and that you can use them to analyse other’s data.
A pie chart is a circle which as a whole represents all the data gathered. Each segment of the 360 degree circle is a different group. To be able to draw a pie chart you must first be able to convert the data we are given into degrees which we will then plot onto the circle.
Let’s work through an example…
|
Children’s favourite type of movie |
Frequency |
|
Comedy |
3 |
|
Horror |
1 |
|
Action |
2 |
|
Science fiction |
4 |
The table above shows the data a teacher gathered when she asked her class of 10 pupils what their favourite type of film was. To work out the angles of each of these pieces of data and their proportions of the 360 degree circle, we must add two columns to our table - one for our workings and one for the angle.
To find the angle we have to divide each piece of data by the total frequency, which in this case is 10 as there are 10 pupils in the teacher’s class. We then times this by 360 to find what proportion of the 360 degree circle each piece of data is; in other words, to find the angle.
|
Children’s favourite type of movie |
Frequency |
Calculations/workings |
Angle |
|
Comedy |
3 |
3/10 x 360 |
108 |
|
Horror |
1 |
1/10 x 360 |
36 |
|
Action |
2 |
2/10 x 360 |
72 |
|
Science fiction |
4 |
4/10 x 360 |
144 |
Once you have done all of your working you can double check you’ve done all the calculations correctly by adding up all the angles. If they add up to 360, you know you’ve done it right!
Now we have our angles, all we need to do is draw out the pie chart. You’ll need to use a protractor to draw out each angle!
Colouring in each segment is always the best way to clearly show which group is which. Don’t forget to include a key!
Now you know how to draw a pie chart and represent data in a much clearer way! If you’re worried about remembering all of this, why not listen to our pie chart song that gives you all this information through memorable lyrics.
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