Create and interpret pie charts showing parts of a whole. Calculate angles and percentages. Convert between fractions, decimals, and percentages in context.
Click on each step to learn how to create accurate pie charts:
Add up all your data values to find the total, then calculate what fraction or percentage each category represents.
Since a circle has 360°, multiply each proportion by 360° to find the angle for each slice of the pie chart.
Draw a circle and use a protractor to mark each angle accurately, starting from the top and moving clockwise.
Label each slice with its category name and value, create a legend with colors or patterns, and add a clear title.
Pie charts show how parts relate to the whole, making it easy to see proportions and compare different categories at a glance.
Hover over the legend items to highlight different sections:
Enter data for up to 4 categories and see your pie chart created instantly:
Immediately see which categories are largest and smallest compared to the whole
Perfect for showing how individual parts contribute to a complete dataset
Easy to compare relative sizes of different categories at a glance
Reinforces understanding of fractions, decimals, and percentages
Data: Red: 8, Blue: 12, Green: 4, Yellow: 16
Total: 8 + 12 + 4 + 16 = 40
Steps:
Data: Math: 6 hrs, English: 5 hrs, Science: 4 hrs, Art: 3 hrs, PE: 2 hrs
Total: 6 + 5 + 4 + 3 + 2 = 20 hours
Steps:
Data: Food: £60, Clothes: £40, Toys: £20, Savings: £80
Total: £60 + £40 + £20 + £80 = £200
Steps:
Problem: Trying to create proportions without knowing the whole amount.
Solution: Always add up all category values to get the total before calculating proportions.
Problem: Calculation errors leading to incorrect total angle.
Solution: Always check that all angles sum to exactly 360°. Adjust rounding if needed.
Problem: Using percentage values as degrees (e.g., 25% ≠ 25°).
Solution: Remember: Percentage × 3.6 = Angle in degrees
Problem: Sloppy angle measurement leading to distorted pie charts.
Solution: Take time to measure angles precisely. Start from 0° each time.
You've mastered pie charts and proportions! Here's what you can now do:
Convert data values to fractions, decimals, and percentages accurately
Transform proportions into precise angles for pie chart slices
Draw accurate pie charts with proper proportions and clear labels
Read pie charts to understand part-to-whole relationships
You've mastered pie charts and proportional thinking
You can now create professional pie charts and work confidently with fractions, decimals, and percentages!
Ready to collect your own data? In Chapter 9.5, you'll learn how to design surveys and gather primary data systematically!