Pie charts | Year 6 Mathematics PDF Download

How to display data

• We can display information in various ways.
• We might write a list, summarize information in a table, draw a bar chart or line graph (considering the scales on both axes), and so on.
• A pie chart is another example of representing data visually.

What are pie charts?

• Pie charts show proportions, such as fractions of a whole, rather than total amounts.
• Fractions, decimals, and percentages are examples of proportions. The circle (360 degrees) represents the whole, and the separate parts (or sectors) fit together to make the entire circle.
• Line graphs and bar charts are statistical diagrams where we can read the amounts by interpreting the scales on the given axes.
• In this part of mathematics, we learn to understand why some methods of displaying data may be more effective than others.

Examples

Example 1: In this example, there are two pie charts. This is because we want to compare the results of two different schools.
Both schools have decided to collect and then display information about recycling ‘Tin cans’ and ‘Plastic bottles’ in their respective schools.

Once again, let’s consider whether the following statement is TRUE or FALSE.
Sol: In School A more plastic bottles were recycled than in School B.
This could be true or it could be false.
This is because we have not been told the total amount of items that have been recycled in each school.
If we knew the total of items, then we could work out what each the amount each sector represents for both of the schools.
However, it would be true to say that in School A a greater proportion of plastic bottles were recycled than in School B.

Example 2: A school decides to organise a special event for all Year 6 pupils in their last term of primary school. The pupils can choose just one of three different options.
The pie chart below shows the results.

Let’s consider whether the following statements are TRUE or FALSE.
Sol: 25% of Y6 pupils chose the Museum of Natural History.
This is true!
If 16 pupils chose the Wildlife Park and this is 20% of all the Y6 pupils, then this means that the pie chart represents a total of 80 pupils.
This is true!
20% is equivalent to one fifth and one fifth of 80 is 16
60% of the pupils chose the Activity Centre.
This is false!
One whole = 100%, so the correct answer is 55% because 55% + 25% + 20% = 100%
The angle of the sector representing the Wildlife Park is 72°.
This is true!
10% of 360 = 36, so 20% of 360 = 36 x 2 = 72
The fraction of the whole pie chart that represents the Activity Centre is eleven twentieths.
This is true!
55% = 55/100 which cancels down to 11/20