Year 4 - Maths
Investigate lines of symmetry in 2D shapes by folding
Properties of 2D and 3D shapes and symmetry
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
In this unit pupils will complete and compose symmetrical shapes from two congruent shapes and investigate lines of symmetry in 2D shapes.
Lesson Summary
You will learn to use folding to investigate lines of symmetry in different 2D shapes.
Key Notes
- When you fold a shape on a line of symmetry, the two halves will match exactly.
- A line of symmetry is not always horizontal or vertical.
- Some quadrilaterals, such as a parallelogram, have no lines of symmetry.
- Others, such as a kite, have one line of symmetry. Others, such as a rectangle, can have more than one line of symmetry.
Vocabulary To Learn
- Kite: A quadrilateral with two pairs of adjacent, equal sides.
- Line of symmetry: If you were to fold a shape on its line of symmetry, both halves would match exactly.
Common Mistakes To Avoid
- Children may not recognise a line of symmetry when it is neither horizontal nor vertical.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
When you fold a shape on a line of symmetry, the two halves will match exactly. A line of symmetry is not always horizontal or vertical.
2. Use this key word in a maths sentence and explain it clearly. 'Kite'
A quadrilateral with two pairs of adjacent, equal sides. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Children may not recognise a line of symmetry when it is neither horizontal nor vertical. Correction: Allow opportunities for exploring lines of symmetry practically by folding cut outs of lots of different shapes. Encourage children to view and describe these in different orientations to help them see that a line of symmetry can be in any direction.
More Lessons In This Unit
- Complete a symmetrical pattern Study Guide
- Diagonal lines of symmetry Study Guide
- Explore symmetry by joining two identical shapes Study Guide
- Explore, sort and classify triangles Study Guide
- Find lines of symmetry in 2D shapes Study Guide
- Identify different types of triangle Study Guide
- Investigate symmetry and symmetrical patterns Study Guide
- Reflect polygons in a line of symmetry Study Guide
- Reflect polygons that are dissected by the line of symmetry Study Guide
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