# Perimeter of Regular and Irregular Shapes (Primary 6)

**MATHEMATICS **

**SECOND TERM**** **

**WEEK 4/P****RIMARY 6**

**WEEK/PRIMARY 5**

**THEME – MEASUREMENTS **

** PREVIOUS LESSON – Second Term Scheme of Work and Plan Lesson Notes for MATHEMATICS Week 1 to Week 12 Primary Schools**

**TOPIC – PERIMETER OF REGULAR AND IRREGULAR SHAPES **

**PERFORMANCE OBJECTIVES **

By the end of the lesson, the pupils should have attained the following objectives (cognitive, affective and psychomotor) and should be able to –

discover that different rectangle with the same area have different perimeters.

**ENTRY BEHAVIOUR **

**INSTRUCTIONAL MATERIALS**

The teacher will teach the lesson with the aid of cardboard showing rectangle of equal rectangle areas but different perimeters.

**METHOD OF TEACHING – Choose a suitable and appropriate methods for the lessons.**

*Note – Irrespective of choosing methods of teaching, always introduce an activities that will arouse pupil’s interest or lead them to the lessons. *

**REFERENCE MATERIALS**

1. Scheme of Work

2. 9 – Years Basic Education Curriculum

3. Course Book

4. All Relevant Material

5. Online Information

**CONTENT OF THE LESSON **** **

**LESSON ONE – INTRODUCTION TO RECTANGLES**

Pupil’s Activities 1 – Properties of Cuboid

**Teacher’s Activities – Questions **

1. The objects below is called ______________.

2. What shape does represent in mathematics?

3. How many faces does the objects has?

4. Many corners or vertices does it have?

5. The object is used for ______________.

6. Mention 5 objects that can be packaged inside.

**Note – Guides or leads the pupils where necessary. **

**Pupil’s Response **

1. Carton or box

2. Cuboid

3. Six (6) faces

4. Eight vertices (corners)

5. Packaging

6. Indomie, wine, milk, television, radio, Maclean, chalk, marker, etc.

Teacher’s/Pupil’s Activities 2 – Introduction to Rectangle

**Teacher’s Activities – Cut one of the faces of the carton. Asks pupils to draw and name it. **

**Pupil’s Response **

**Rectangle **

Pupil’s Activities 3 – Lengths of Rectangle

**Instructions/Questions **

1. Measure each length of the rectangle.

2. Compare each length with another.

3. Use measurements to describe what rectangle means.

4. Mention 5 objects with rectangular face or shape.

**Pupil’s Response **

1. 10 cm, 7 cm, 10 cm and 7cm.

2. Two of the lengths are equal to each other.

3. Rectangle is a shape with 4 length. Two of its lengths are equal to another.

4. Board, sheet of paper, door, wall or floor, top of desk, etc.

**Teacher’s remark – A rectangle is a 4 sided with opposite parallel lengths are eual length. It is one of the group called quadrilateral. **

**LESSON TWO – PERIMETER OF A RECTANGLE**

Pupil’s Activities 1 – Measurement of Rectangles

Draw two (2) rectangles with 7 cm by 3 cm

Pupil’s Activities 2 – Perimeter of a Rectangle

Add the lengths of the rectangle drawn.

7 cm + 3 cm + 7 cm + 3 cm

= 20 cm.

**Teacher’s remark – The sum of the lengths of a rectangle is called perimeter of a rectangle. 7 cm + 7 cm + 3 cm + 3 cm = 20 cm. What is perimeter? **

Teacher’s/Pupil’s Activities 2 – Perimeter of A Rectangle

Find the perimeter of the rectangle.

Perimeter (P) of a rectangle,

= a + b + a + b

= a + a + b + b

= 2a + 2b

= 2 (a + b)

Pupil’s Activities 3 – Exercises/Assignment

- Find the perimeter of

- Draw a rectangle of 15 cm by 8 cm and 8 by 10 cm.

**LESSON THREE – PERIMETER IRREGULAR SHAPES **

Pupil’s Activities 1 – Regular and Irregular Shapes

Examine the shape and compare it with a rectangle.

**Teacher’s remark – Listen to the pupils and discuss the number of rectangle in the irregular shape. **

Teacher’s/Pupil’s Activities 2 – Perimeter of Irregular Shapes1. How many lengths does the below shape has?

2. Name each length A to F.

3. What is D and E?

**Guide pupils in this activities. **

**Pupil’s Response,**

A = 12, B = 10, C = 7, D = 10 – 2, E = 12 – 7 and F = 2

Perimeter (p)

= 12 + 10 + 7 + (10 – 2) + (12 – 7) + 2

= 12 + 10 + 7 + 8 + 5 + 2

= 44.

Pupil’s Activities 3 = Exercises/Take Home

Find the perimeter

**LESSON FOUR – PERIMETER OF A SQUARE**

Pupil’s Activities 1 – Measurement of Square

Measure the lengths of the square and rectangles. What is the different between their lengths?

**Pupil’s comment – The square has equal lengths. While the rectangle has the opposite lengths equal. **

Pupil’s Activities 2 – Perimeter of a Square

**Teacher’s comment – Perimeter is the sum of the lengths of a plane shapes. **

Find the perimeter of square in activities 1.

Pupil’s Activities 3 – Perimeter of a square (4L)

Perimeter (P)

= L + L + L + L

= 4L

Pupil’s Activities 4 – Exercises/Take Home

**LESSON FIVE – RECTANGLES OF THE SAME AREA HAVING DIFFERENT PERIMETERS**

Pupil’s Activities 1 – Rectangles with the same area and different perimeters.

Measure and find the areas of the following rectangles,

**Rectangle A **

Length – 8 cm

Breadth – 5 cm

Area = Length x Breadth

= 8 cm x 5 cm

= 40 cm²

**Rectangle B**

Length – 10 cm

Breadth – 4 cm

Area = 10 cm x 4 cm

= 40 cm²

Pupil’s Activities 2 – Find the perimeter of the rectangles in activities 1

**Rectangles A **

Perimeter = 2(8 cm + 5 cm)

= 2 x 13 cm

= 26 cm.

**Rectangle B **

Perimeter = 2 (10 cm + 4 cm)

= 2 x 14 cm

= 28 cm.

Teacher’s remark – The two rectangles have the same area (40 cm2) but have different perimeters. Their perimeters are 26 cm and 28 cm respectively.

Pupil’s Activities – Exercises/Take Home

Copy and complete the following table and obtain different rectangles with the same area.

**PRESENTATION**

To deliver the lesson, the teacher adopts the following steps:

1. To introduce the lesson, the teacher revises the previous lesson. Based on this, he/she asks the pupils some questions;

2. Guides pupils to draw two rectangles of dimensions 7 cm by 3 cm and 1o cm by 15cm.

Pupil’s Activities – Find the perimeters of the two rectangles.

3. Guides pupils to prove that they have equal area but different perimeters.Pupil’s Activities – Compare their results.

**CONCLUSION**

- To conclude the lesson for the week, the teacher revises the entire lesson and links it to the following week’s lesson.

- Next Lesson –
**Second Term Scheme of Work and Plan Lesson Notes for MATHEMATICS Week 1 to Week 12 Primary Schools**

**LESSON EVALUATION **

**Pupils to calculate perimeters of rectangles with equal areas but with different lengths and breadths.**