Knowledge Organiser: Pie Charts
Part of Pie Charts · GCSE GCSE Mathematics revision
This topic summary covers Knowledge Organiser: Pie Charts within Pie Charts for GCSE Mathematics. Revise Pie Charts in Statistics for GCSE Mathematics with 14 exam-style questions and 20 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 8 of 8 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 8 of 8
Practice
14 questions
Recall
20 flashcards
Knowledge Organiser: Pie Charts
Key Terms
- Sector: A slice of a pie chart representing one category
- Sector angle: The angle of a slice, proportional to the data value
- Proportion: Each category's share of the total (value ÷ total)
- Protractor: Tool used to measure and draw sector angles accurately
- Legend/key: Identifies which colour or pattern represents each category
Must-Know Facts
- All sector angles must add up to exactly 360°
- A full circle always represents the total of the data
- Start drawing from the 12 o'clock position, measure clockwise
- Largest sectors are easiest to draw first
- Pie charts show proportions — they cannot easily compare totals between two charts
- Best used for 2–6 categories; too many slices become hard to read
- To find a value from an angle: value = (angle ÷ 360°) × total
Key Formulas
- Sector angle = (value ÷ total) × 360°
- Value from angle = (angle ÷ 360°) × total
- Percentage = (value ÷ total) × 100%
- Percentage from angle = (angle ÷ 360°) × 100%
Common Mistakes
- Angles not summing to 360°: Always check your sector angles add up to exactly 360° before drawing
- Using percentage instead of frequency: Calculate angle using the actual frequency divided by total, not by percentage
- Measuring angles inaccurately: Use a protractor carefully — start from the same baseline for each sector
- Comparing pie charts of different sizes: Pie charts show proportions, not totals — you cannot compare totals from pie charts alone
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Practice Questions for Pie Charts
A pie chart shows the results of a survey about favourite holiday destinations. The sectors have the following angles: - Beach: 144° - City: 90° - Countryside: 72° - Mountains: 54° Which destination is the modal category?
A newspaper reports that a pie chart shows Company A has a 'dominant market share' in the smartphone industry, with their sector taking up nearly half the chart. A critic argues that the pie chart is misleading. Explain two limitations of using a pie chart in this context, and suggest what additional information would make the chart more useful.
Quick Recall Flashcards
14 questions on Pie Charts — practise free
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