Mathematics

Intermediate

50 mins

Teacher/Student led

Learning Goals

Learning Outcomes

Lesson Files

+80 XP

Teacher-led from the board. Pupils do not need a device, but can follow on one.

What you need:
IWB/Projector/Large Screen
Paper shapes

Line Symmetry: Finding Lines of Symmetry

Explore lines of symmetry by folding shapes and letters so their two halves match exactly. Test whether each fold is a true line of symmetry and discover how many lines different shapes have.

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1 Getting Started
2 Watch and Notice
3 Try It Together
4 Rule the Lines in Your Copy
5 Class Challenge
6 What Did We Notice?
7 What's Next
Pupil practice

Your turn

Your teacher is running this lesson on the board. Here is the part you can try yourself.

Your written work is on page 84

Symmetry tool

1 - Getting Started ~5 mins

Illustration for Getting Started Watch as I fold this paper heart straight down the middle. The fold I make is a mirror line: the line we test to see whether the two halves match. Look closely: the two halves land exactly on top of each other, like a mirror.

Key point

A square is different. Where could you fold a square so that both halves match perfectly? Is there only one fold that works, or could there be more than one?

👇 Mark your steps as done as you complete them.

+5 XP

2 - Watch and Notice ~11 mins

Watch the mirror line move across four shapes: a square, a rectangle, the letter X and the letter T. Each fold either makes two halves that match or it doesn't. Count how many folds match for each one.

👇 Mark your steps as done as you complete them.

+10 XP

3 - Try It Together ~13 mins

Today we explore: tap to place the mirror line, the fold line we test, on each shape and letter to see whether the two halves match. We will work through a square, a rectangle, the letter T and the letter X on the shared board.

Key point

When the fold makes both halves land exactly on top of each other, we have found a line of symmetry. When they miss, that fold does not count.

Test the fold lines

+15 XP

4 - Rule the Lines in Your Copy ~5 mins

COPYBOOK MOMENT

In your maths copy, draw a square, a rectangle and the letter X. Then rule in every line of symmetry you can find on each one. Use the straight edge of your ruler to keep your lines neat.

+10 XP

5 - Class Challenge ~10 mins

Today we work through these together: the letter H, the letter X, the letter S and the letter M.

Watch out

Watch out — one of them has no line of symmetry at all, so check every fold carefully before you decide.

Find every line of symmetry

+15 XP

Pupil practice

Module 8 · Symmetry, Location and Transformation Shape & Space

Lesson 91 · Line Symmetry: Finding Lines of Symmetry

Download Activity Book page (PDF)

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