Pie Charts
Show parts of a whole as sectors.
Key idea
Show parts of a whole as sectors.
In depth
A pie chart shows parts of a whole as angles: angle = (value ÷ total) × 360°. It works best for a few categories that add up to 100%. Small differences are hard to see.
Worked example
If 30 of 120 students walk to school, the slice is 30/120 × 360° = 90°.
Formula
Real-world uses
- Showing budget shares, market share and how a day is spent
Common mistake
Using a pie chart for data that does not make up a whole.
How to learn this
- Read the key idea and say it in your own words.
- Work through the worked example, then try a similar problem.
- Use the interactive lesson’s visual and mini-quiz to check the pattern.
Frequently asked questions
What is Pie Charts?
Show parts of a whole as sectors. It is a topic at the beginner level in Probability & Statistics.
What is the formula for Pie Charts?
The key formula is angle = (part/total) × 360°.
Where is Pie Charts used in real life?
Real-world examples: Showing budget shares, market share and how a day is spent.
What should I learn before Pie Charts?
Make sure you are comfortable with Bar Graphs, the previous topic in Probability & Statistics.
What is a common mistake with Pie Charts?
Using a pie chart for data that does not make up a whole.
How can I practise Pie Charts?
Open the interactive lesson, play with the visual, then answer the three-question mini-quiz. Getting two right marks the topic complete.
What comes after Pie Charts?
Move on to Line Graphs next.
Related beginner topics in Probability & Statistics
- Types of Data – Categorical vs numerical, discrete vs continuous.
- Frequency Tables – Count how often each value occurs.
- Tally Charts and Pictographs – Simple visual summaries of counts.
- Bar Graphs – Compare categories using bars.
- Line Graphs – Show change over time.
- Mode – The most frequent value.