EDEXCEL GCSE FOUNDATION MATHS - What are Pie Charts

Edexcel GCSE Foundation Maths: Pie Charts

What is a Pie Chart?

A pie chart is a circular graph that shows the proportion of a whole that each category represents. It's like dividing a pie into slices, where each slice represents a different part of the whole.

Key Features of a Pie Chart:

• Circle: The whole pie represents the entire data set.
• Slices: Each slice represents a different category.
• Size of the slice: The size of the slice is proportional to the amount of data it represents.
• Labels: Each slice is labelled with the category it represents.
• Percentage or angle: The percentage or angle of each slice can be shown to represent the proportion of the whole.

Example:

Imagine a pie chart showing the favourite colours of 20 students:

• Red: 8 students
• Blue: 6 students
• Green: 4 students
• Yellow: 2 students

Steps to Create a Pie Chart:

1. Calculate the proportion: For each category, divide the number of students by the total number of students (20).
2. Red: 8/20 = 0.4
3. Blue: 6/20 = 0.3
4. Green: 4/20 = 0.2
5. Yellow: 2/20 = 0.1
6. Convert to percentages: Multiply each proportion by 100.
7. Red: 0.4 x 100 = 40%
8. Blue: 0.3 x 100 = 30%
9. Green: 0.2 x 100 = 20%
10. Yellow: 0.1 x 100 = 10%
11. Calculate the angle: To find the angle of each slice, multiply the percentage by 360 degrees (a full circle).
12. Red: 40% x 360° = 144°
13. Blue: 30% x 360° = 108°
14. Green: 20% x 360° = 72°
15. Yellow: 10% x 360° = 36°
16. Draw the pie chart: Using a compass, draw a circle. Using a protractor, draw the angles of each slice. Label each slice with the category and the percentage.

Advantages of Pie Charts:

• Easy to understand and interpret.
• Visually appealing.
• Show the proportions of a whole.

Disadvantages of Pie Charts:

• Difficult to compare different pie charts.
• Not suitable for large datasets.
• Cannot show precise values.

Applications of Pie Charts:

Pie charts are used in various fields:

• Business: Show market share, sales figures, and customer demographics.
• Education: Represent student performance, subject choices, and attendance.
• Health: Show disease prevalence, population demographics, and health trends.
• Finance: Represent income sources, expenses, and portfolio allocation.

Practice Problems:

1. Create a pie chart showing the favourite sports of 30 students:
2. Football: 15
3. Basketball: 8
4. Tennis: 5

5. Swimming: 2

6. A survey of 100 people was conducted to find their favourite type of music:

7. Pop: 40
8. Rock: 30
9. Classical: 20
10. Jazz: 10
11. Create a pie chart to represent this data.

Remember:

• The total percentage of all slices in a pie chart should always add up to 100%.
• The angles of all slices in a pie chart should always add up to 360°.

By understanding the concept of pie charts, you can effectively interpret data and communicate information visually in various contexts.