Year 4 - Maths
Explore, sort and classify triangles
Properties of 2D and 3D shapes and symmetry
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Study Guides
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 sort triangles in different ways based on their properties.
Key Notes
- There are three types of triangle - equilateral, isosceles and scalene.
- Some triangles can also be described as right-angled triangles if one of the angles is equal to 90°
- Right-angled triangles can be classified as scalene or isosceles.
Vocabulary To Learn
- Right-angled triangle: A right-angled triangle has one 90° angle. Right-angled triangles can be classified as isosceles or scalene.
- Equilateral triangle: Equilateral triangles have 3 equal sides and 3 equal angles.
- Isosceles triangle: Isosceles triangles have 2 equal sides and 2 equal angles.
- Scalene triangle: Scalene triangles have no equal sides and no equal angles.
Common Mistakes To Avoid
- Children might find it difficult to create triangles with equal angles.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
There are three types of triangle - equilateral, isosceles and scalene. Some triangles can also be described as right-angled triangles if one of the angles is equal to 90°.
2. Use this key word in a maths sentence and explain it clearly. 'Right-angled triangle'
A right-angled triangle has one 90° angle. Right-angled triangles can be classified as isosceles or scalene. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Children might find it difficult to create triangles with equal angles. Correction: Allow time to play and explore constructing triangles using items such as lolly sticks and matchsticks. Develop children's understanding of angles in a triangle using angle strips to check whether the angles are equal or not.
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
- Find lines of symmetry in 2D shapes Study Guide
- Identify different types of triangle Study Guide
- Investigate lines of symmetry in 2D shapes by folding 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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