Representing Data Using Pie Chart – Primary 5 Mathematics First Term Lesson Note

This Primary 5 Mathematics First Term lesson note on representing data using a pie chart helps pupils understand how a circle can show parts of a whole. Pupils learn the meaning of a pie chart, identify sectors, convert simple data into angles and interpret information from a chart.

Lesson Information

Subject: Mathematics
Class: Primary 5 (Basic 5)
Term: First Term
Week: 2
Topic: Representing Data
Sub-topic: Pie Chart
Duration: 40 minutes

Learning Objectives

By the end of the lesson, pupils should be able to:

explain what a pie chart is;
identify the whole, sectors and angles in a pie chart;
calculate simple sector angles from given data;
draw and label a simple pie chart with guidance; and
interpret information presented in a pie chart.

Keywords

Data, pie chart, circle, sector, angle, fraction, percentage, proportion and degrees.

Set Induction

Ask pupils to imagine a round birthday cake shared among friends. If some children receive chocolate slices, some vanilla and others strawberry, the complete cake represents the whole while each slice represents a part. Explain that a pie chart uses the same idea to display data as parts of a circle.

Entry Behaviour and Materials

Pupils should already know how to count, add numbers and read simple tables or charts. Materials include a compass, protractor, ruler, pencil, chart paper, coloured pencils and a sample data table.

Meaning of a Pie Chart

A pie chart is a circular diagram used to represent data as parts of a whole. The entire circle represents 100% or 360°. Each part is called a sector, and the size of a sector shows the proportion represented by that category.

A large sector represents a larger share of the total, while a small sector represents a smaller share.

How to Calculate an Angle

To draw a pie chart, convert each category into an angle using:

Angle = (Category ÷ Total) × 360°

Worked Example

Suppose 20 Primary 5 pupils were asked about their favourite fruits:

Fruit	Number of pupils	Angle
Mango	10	180°
Orange	5	90°
Banana	3	54°
Watermelon	2	36°
Total	20	360°

For mango: (10 ÷ 20) × 360° = 180°. The same method is used for the other categories. The angles must add up to 360°.

Steps for Drawing a Simple Pie Chart

Find the total number of observations.
Calculate the angle for each category.
Use a compass to draw a circle.
Use a protractor to measure each angle from the centre.
Label each sector clearly.
Add a title and, where necessary, a key or legend.

Teacher and Learner Activities

Teacher’s activities: Revise data representation, explain the meaning of a pie chart, demonstrate the angle formula, draw a sample chart and guide pupils through a simple example.

Learners’ activities: Observe the demonstration, calculate angles, identify sectors, draw a guided pie chart and explain what the different sectors represent.

Class Activity

Use this data about how 12 pupils travel to school: Bus – 6, Car – 3, Walking – 2, Motorcycle – 1.

Find the angle for each category.
Draw a circle.
Use a protractor to create the four sectors.
Label and colour the sectors.
State which category has the largest share.

Evaluation Questions

What is a pie chart?
What does the whole circle represent?
How many degrees are in a complete circle?
What is a sector?
Which instrument is used to measure the angles of the sectors?
Calculate the angle for a category containing 5 out of 20 pupils.
Why is it important for all the sectors to add up to 360°?

Common Mistakes to Avoid

Do not confuse the number of observations with the angle.
Remember that a complete circle is 360°, not 100°.
Check that all calculated angles total 360°.
Use the centre of the circle when measuring each sector.

Frequently Asked Questions

What does a pie chart show?

It shows how different categories make up a whole.

What is a sector?

A sector is one part or slice of a pie chart.

Can a pie chart show percentages?

Yes. The complete circle represents 100%, and each sector represents a percentage of that whole.

What is the total angle of a pie chart?

The complete circle is 360°.

Assessment

Define a pie chart.
State the total angle in a circle.
Name two instruments used to draw a pie chart.
Explain what a large sector represents.
Draw a simple pie chart from data provided by your teacher.

Conclusion

Guide pupils to explain that a pie chart represents data as sectors of a circle. Review the relationship between the total data, 360° and the size of each sector. Allow pupils to correct their drawings before submitting their work.

Homework

Ask 10 family members or classmates about their favourite Nigerian fruits. Record the results in a table and, with adult or teacher guidance, calculate the angles needed to represent the data in a pie chart.