Year 3 - Maths
Identify properties of triangles
Right angles
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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 rotate 2 lines around a fixed point to make different angles. They identify vertices and describe half, quarter and three-quarter turns in terms of right angles.
Lesson Summary
You will learn to use different properties to identify and sort triangles.
Key Notes
- Triangles always have three sides, vertices and angles.
- Triangles always have straight sides and sharp vertices.
- Triangles can have right angles.
- Vertices are the corners of a shape.
Vocabulary To Learn
- Triangle: A polygon with three straight sides.
- Vertex: The point where two lines meet.
- Vertices: More than one vertex.
- Properties: A character or quality that something has.
Common Mistakes To Avoid
- Pupils may see other shapes and collections of lines as triangles when they are not (e.g. shapes with rounded corners, three lines that do not all meet).
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Triangles always have three sides, vertices and angles. Triangles always have straight sides and sharp vertices.
2. Use this key word in a maths sentence and explain it clearly. 'Triangle'
A polygon with three straight sides. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Pupils may see other shapes and collections of lines as triangles when they are not (e.g. shapes with rounded corners, three lines that do not all meet). Correction: Provide pupils with shapes, and explore shapes in the environment, classifying them as 'triangles' and 'not triangles'. Ask children, 'Does this shape have three straight sides? Does it have clearly defined, sharp vertices?'.
More Lessons In This Unit
- Identify and describe right angles Study Guide
- Identify properties of quadrilaterals Study Guide
- Investigate and draw other polygons with right angles Study Guide
- Investigate the shapes made when rectangles are cut on the diagonal Study Guide
- Join four right angles at a point using different right-angled polygons Study Guide
- Know that a rectangle is a four-sided polygon with four right angles Study Guide
- Know that a right angle describes a quarter turn Study Guide
- Know that a square is a rectangle in which the four sides are of equal length Study Guide
- Make different sized angles by rotating two lines around a fixed point Study Guide
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