Find lines of symmetry in 2D shapes | Maths | Quizalize & Oak National Academy

Starter quiz

A __________ is a quadrilateral with two pairs of adjacent sides that are equal in length.
- trapezium
- kite ✓
- hexagon
Adjacent means ...
- opposite
- next to ✓
- joining at right angles
This kite is also a square. It has ______ lines of symmetry.
- '4' ✓
Look at these rectangles. Which does not show a line of symmetry?
- a)
- b) ✓
- c)
Which of these shapes has more than one line of symmetry?
- a) ✓
- b)
- c)
Which shape has been incorrectly sorted?
- a) ✓
- b)
- c)
- d)

Exit quiz

A mirror line is also called the line of __________.
- match exactly
- symmetry ✓
- symmetrical
A square is a regular polygon. What is true for all polygons?
- They all have 4 sides.
- They have two equal sides.
- They have all equal sides and all equal angles. ✓
- They have a right angle.
Match each shape shown to the number of lines of symmetry it has.
- pentagon
  
  ⇔
  
  1 ✓
- rectangle
  
  ⇔
  
  2 ✓
- square
  
  ⇔
  
  4 ✓
This shape is a regular hexagon. It has ______ lines of symmetry.
- '6' ✓
The number of lines of symmetry in a regular polygon is __________ the number of sides it has.
- less than
- equal to ✓
- greater than
Match the number of lines of symmetry to the shapes.
- square
  
  ⇔
  
  4 lines of symmetry ✓
- equilateral triangle
  
  ⇔
  
  3 lines of symmetry ✓
- regular pentagon
  
  ⇔
  
  5 lines of symmetry ✓
- regular octagon
  
  ⇔
  
  8 lines of symmetry ✓
- regular hexagon
  
  ⇔
  
  6 lines of symmetry ✓

Worksheet

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Presentation

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Lesson Details

Key learning points

A line of symmetry splits the shape into two equal parts which are mirror images.
Shapes are symmetrical when they look the same when a mirror is placed on the mirror line.
Regular polygons have the same number of lines of symmetry as they have sides.

Common misconception

Children may not identify lines of symmetry that are neither horizontal nor vertical.

Allow opportunities for children to handle and manipulate cut outs of shapes so that they can try to find lines of symmetry in different orientations. Encourage them to describe the position of the line of symmetry to support their understanding.

Keywords

Symmetrical - When a shape, pattern or image has one half that is the reflection of the other half, it can be described as symmetrical.
Line of symmetry - If you were to fold a shape on its line of symmetry, both halves would match exactly.
Regular polygon - A regular polygon has sides that are all equal and angles that are all equal.