Pie Charts & Data Display
Pie charts show how data is divided into parts. Each slice represents a proportion of the whole.
What You Need to Know
Key Concept Diagram
A pie chart shows parts of a whole as sectors of a circle
Each sector angle = (frequency ÷ total) × 360°
Pie charts are best for showing proportions, not exact values
Compare pie charts to bar graphs for different purposes
Key Vocabulary
Sector
A slice of a pie chart representing a category
Proportion
The fraction or percentage of the total
Frequency
How often each value occurs in the data
Legend
A key showing what each colour or pattern represents
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
In a pie chart of 40 students' favourite sports, 10 chose swimming. What angle does the swimming sector have?
Question 2
A pie chart has a sector of 120°. What fraction of the total does this represent?
Question 3
Which type of graph is BEST for showing proportions of a whole?
Key Concepts Summary
- ●A pie chart shows parts of a whole as sectors of a circle
- ●Each sector angle = (frequency ÷ total) × 360°
- ●Pie charts are best for showing proportions, not exact values
- ●Compare pie charts to bar graphs for different purposes