Pie Chart Introduction
A pie chart is a circular chart divided into slices. Each slice represents a part of the whole. The bigger the slice, the larger the share it represents.
In Class 4, you will learn to read pie charts, understand what the slices represent, and answer questions based on pie chart data.
What is Pie Chart Introduction - Class 4 Maths (Data Handling)?
A pie chart (or circle graph) is a circle divided into sectors (slices) that show how a whole is split into parts. The entire circle represents the total (100%).
Key features:
- The whole circle = total data (100%).
- Each slice shows one category's share.
- Larger slices = larger values.
- All slices together make the complete circle.
Pie Chart Introduction Formula
Each slice = (Part ÷ Whole) × 100%
or
Value of a slice = (Percentage ÷ 100) × Total
A full circle = 360°. A quarter of the circle = 90° = 25%. Half the circle = 180° = 50%.
Types and Properties
Reading a pie chart:
- Half the circle (50%) — one category takes half the total.
- Quarter of the circle (25%) — one category is one-fourth of the total.
- Small slice — that category has a small share.
Pie charts are best for showing parts of a whole — like how ₹100 pocket money is spent on different things.
Solved Examples
Example 1: Example 1: Reading a simple pie chart
Problem: A pie chart shows Ria's daily activities. Sleep takes up half the circle, school takes a quarter, and play and homework share the rest equally. How many hours for each if the total is 24 hours?
Solution:
Step 1: Sleep = half = 24 ÷ 2 = 12 hours.
Step 2: School = quarter = 24 ÷ 4 = 6 hours.
Step 3: Remaining = 24 − 12 − 6 = 6 hours. Play and homework share equally: 6 ÷ 2 = 3 hours each.
Answer: Sleep = 12 hrs, School = 6 hrs, Play = 3 hrs, Homework = 3 hrs.
Example 2: Example 2: Identifying the largest category
Problem: A pie chart shows favourite sports: Cricket = largest slice, Football = second largest, Badminton = small, Kabaddi = smallest. Which sport is most popular?
Solution:
Step 1: The largest slice represents the most students.
Answer: Cricket is the most popular sport.
Example 3: Example 3: Percentage to value
Problem: In a class of 40 students, a pie chart shows 25% like maths, 30% like science, 20% like English, and 25% like Hindi. How many students like science?
Solution:
Step 1: Science = 30% of 40.
Step 2: (30 ÷ 100) × 40 = 12 students.
Answer: 12 students like science.
Example 4: Example 4: Finding the value from fraction
Problem: A pie chart shows that 1/4 of ₹200 pocket money is spent on books. How much is that?
Solution:
Step 1: 1/4 of ₹200 = 200 ÷ 4 = ₹50.
Answer: ₹50 is spent on books.
Example 5: Example 5: Comparing slices
Problem: A pie chart of 60 students shows: Mango (half the circle), Apple (quarter), Banana (rest). How many students like banana?
Solution:
Step 1: Mango = 1/2 of 60 = 30.
Step 2: Apple = 1/4 of 60 = 15.
Step 3: Banana = 60 − 30 − 15 = 15.
Answer: 15 students like banana.
Example 6: Example 6: Pocket money pie chart
Problem: Dev gets ₹100 pocket money. He spends 40% on snacks, 25% on stationery, 20% saves, and 15% on games. Find the amount for each.
Solution:
Step 1: Snacks = 40% of 100 = ₹40.
Step 2: Stationery = 25% of 100 = ₹25.
Step 3: Savings = 20% of 100 = ₹20.
Step 4: Games = 15% of 100 = ₹15.
Step 5: Verify: 40 + 25 + 20 + 15 = ₹100 ✓
Answer: Snacks = ₹40, Stationery = ₹25, Savings = ₹20, Games = ₹15.
Example 7: Example 7: Pie chart vs bar graph
Problem: When should you use a pie chart instead of a bar graph?
Solution:
Step 1: Pie chart → shows parts of a whole (how a total is divided).
Step 2: Bar graph → compares different categories or groups.
Answer: Use a pie chart to show how something is split into parts (e.g., how ₹100 is spent). Use a bar graph to compare separate items (e.g., marks in different subjects).
Example 8: Example 8: Half and quarter slices
Problem: In a pie chart of 80 students, half chose red and a quarter chose blue. How many chose other colours?
Solution:
Step 1: Red = 1/2 of 80 = 40.
Step 2: Blue = 1/4 of 80 = 20.
Step 3: Others = 80 − 40 − 20 = 20.
Answer: 20 students chose other colours.
Example 9: Example 9: Check all slices add up
Problem: A pie chart shows: A = 35%, B = 25%, C = 15%, D = ?. Find D.
Solution:
Step 1: Total must be 100%.
Step 2: D = 100% − 35% − 25% − 15% = 25%.
Answer: D = 25%.
Key Points to Remember
- A pie chart is a circle divided into slices showing parts of a whole.
- The whole circle = 100% (or the total number).
- A larger slice means a larger share.
- Half the circle = 50%. Quarter = 25%.
- All slices must add up to 100% (or the total).
- Pie charts are best for showing how a total is divided.
- Bar graphs are better for comparing separate categories.
Practice Problems
- A pie chart shows 50% of 80 students like cricket. How many students is that?
- In a pie chart, slices show 40%, 30%, 20%. What percentage is the missing slice?
- Aman gets ₹200 pocket money. He saves 25%. How much does he save?
- A pie chart has 4 equal slices. What percentage does each slice represent?
- A class of 60 students: 1/3 walk to school, 1/2 take a bus, rest come by car. How many come by car?
- Which is bigger in a pie chart: a slice showing 35% or a quarter of the circle?
- Draw a simple pie chart showing: Half = maths, Quarter = science, Quarter = English.
Frequently Asked Questions
Q1. What is a pie chart?
A pie chart is a circle divided into slices where each slice shows a part of the whole. The full circle represents 100% or the total.
Q2. Why is it called a pie chart?
Because it looks like a pie or roti cut into slices. Each slice is a portion of the whole.
Q3. What does the size of a slice tell us?
A bigger slice means that category has a larger share of the total. A smaller slice means a smaller share.
Q4. What should all the slices add up to?
All slices must add up to 100% or to the full total number. If they do not add up, the pie chart has an error.
Q5. When should I use a pie chart instead of a bar graph?
Use a pie chart to show how a total is divided into parts (e.g., how time is spent in a day). Use a bar graph to compare different groups or categories.
Q6. How do you find the value of a slice?
Multiply the percentage by the total and divide by 100. If a slice is 30% and the total is 200: value = (30/100) × 200 = 60.
Q7. Can a pie chart have more than 5 slices?
Yes, but too many slices make the chart hard to read. If there are many small categories, they are often grouped into 'Others'.
Q8. How is a quarter of a pie chart written as a percentage?
A quarter = 1/4 = 25%. This means the slice takes up 25% of the total.
