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MEP Jamaica: STRAND I
UNIT 31 Angles and Symmetry: Lesson Plans
STRAND I: Geometry and Trigonometry
UNIT 31: Angles and Symmetry
Lesson 31.2 Line and Rotational Symmetry
CSEC Objective: line and rotational symmetry
Lessons Aims:
After this lesson, the student should be able to:
i)
identify the rotational symmetry and line symmetry of
2-dimensional shapes.
Prerequisite Knowledge: Familiarity with 2-D shapes
Key Vocabulary:
rotational symmetry, line symmetry
Challenges:
Although students will have seen this before, there might be
confusion regarding rotational and line symmetry.
Teaching Notes:
Ensure that all students can distinguish between rotational and
line symmetry and, in particular, can understand that some
shapes have no rotational symmetry.
PowerPoints:
PP 31.1
Lesson Plans:
Review homework
Introduction
Exercises
Review answers
Exercises
Review answers
Activity
Closing activity
Homework
Relevant CSEC Questions:
Glossary of Terms:
 CIMT and e-Learning Jamaica
DS 31.1 or ST 31.2, WE1
ST 31.2, Q1 and Q2
ST 31.2, Q3 and Q4
Activity 31.1
ST 31.2, Q5
ST 31.2, Q13 or Activity 31.2
RT Q1 and Q2
An object has rotational symmetry if it can be
rotated about a point so that it fits on top of
itself without completing a full turn.
The shapes opposite have rotational
Order 2
symmetry.
Shapes have line symmetry if a mirror could
be placed so that one side is an exact reflection
of the other. These imaginary 'mirror lines'
are indicated by dotted lines in the diagrams 2 lines of
shown opposite.
symmetry
Order 4
4 lines of
symmetry