TOPIC: PERIMETER OF PLANE SHAPES
A: TEACHING AND LEARNING MATERIALS
- Ruler.
- Cut-out squares.
- Cut-out rectangles and triangles.
- Measuring tape.
- Pupils’ writing books and pencils.
B: REFERENCE MATERIALS
- Scheme of work.
- Recommended Mathematics textbook for Primary 3.
- Online educational resources.
C: PREVIOUS KNOWLEDGE
The pupils can measure the length of objects using centimetres and metres.
D: PERFORMANCE OBJECTIVES
By the end of the lesson, pupils should be able to:
- Explain the meaning of perimeter.
- Measure the sides of simple shapes.
- Find the perimeter of a square.
- Find the perimeter of a rectangle.
- Find the perimeter of a triangle.
E: CONTENT
Meaning of Perimeter
Perimeter is the total distance around a shape.
To find the perimeter, we add the lengths of all the sides.
Perimeter of a Square
A square has four equal sides.
Example:
Each side = 4 cm
Perimeter:
4 + 4 + 4 + 4 = 16 cm
Therefore, the perimeter is 16 cm.
Perimeter of a Rectangle
Example:
Length = 6 cm
Width = 3 cm
Perimeter:
6 + 3 + 6 + 3 = 18 cm
Perimeter of a Triangle
A triangle has three sides.
Example:
Sides = 4 cm, 5 cm and 6 cm
Perimeter:
4 + 5 + 6 = 15 cm
F: LESSON PRESENTATION
F1: Teachers’ Activities
- Revises measurement of length.
- Introduces the meaning of perimeter.
- Shows pupils different plane shapes.
- Measures the sides of shapes with a ruler.
- Demonstrates how to add the sides.
- Gives pupils simple perimeter exercises.
F2: Pupils’ Activities
- Identify the sides of shapes.
- Measure the sides with a ruler.
- Add the sides of squares.
- Find the perimeter of rectangles.
- Find the perimeter of triangles.
- Solve simple exercises.
G: CONCLUSION
The teacher revises perimeter and reminds pupils that perimeter means the total distance around a shape.
The teacher corrects pupils where necessary.
H: EVALUATION GUIDE
Pupils should be able to answer the following questions:
- What is perimeter?
- Find the perimeter of a square with sides of 3 cm.
- Find the perimeter of a square with sides of 5 cm.
- Find the perimeter of a rectangle with sides 6 cm, 4 cm, 6 cm and 4 cm.
- Find the perimeter of a triangle with sides 3 cm, 4 cm and 5 cm.
- How many sides does a square have?
- What do we do with the sides to find the perimeter?