Third Term Lesson Note for Week Ten
CLASS: Primary 3
SUBJECT: Mathematics
TOPIC: Lines of Symmetry
Duration : 80 minutes
Period : Double Periods
Reference Book :
- New Method Mathematics for Primary Schools, Book 3 .
- Lagos State Unified Schemes of Work for Primary Schools (Primary 1 – 3)
- Online Resources
Instructional Material : Pictorial chart showing line of symmetry of some shapes
Learning Objectives :By the end of the lesson learners will be able to
i. Define lines of symmetry
ii. Give examples using plane shapes.
iii. Identify the lines of symmetry in different shapes .
CONTENT:
The line of symmetry can be defined as the axis or imaginary line that passes through the center of the shape or object and divides it into identical halves.
For example, if we fold a figure cut out exactly at the center vertically, its halves will be congruent. The line of the fold is the line of symmetry.
Shapes which balance over a line are called Symmetrical Shapes. The balance line is called a line of symmetry.
For examples :
A square has 4 lines of symmetry.
A rectangle has two lines of symmetry.
An isosceles triangle has one line of symmetry.
An equilateral triangle has three lines of symmetry.
Presentation Steps :
Step 1 : Revises the previous lesson with the learners by asking them questions orally.
Step 2 : Introduces the new topic by explaining lines of symmetry.
Step 3 : Identify the lines of symmetry of different shapes.
Evaluation :
1. ___________ is a line that divides a shape into two equal parts when folded.
2. How many lines of symmetry has a rectangle? (a) 2 (b) 4 (c) 1
3. Which of the shape has four lines of symmetry? (a) rectangle (b) square (c) triangle
Conclusion : At the end of the lesson learners were able to answer the questions. The teacher marks their notebooks and makes necessary corrections.