Identify properties of triangles
Lesson details
Learning outcome
I can use different properties to identify and sort triangles.
Key learning points
- 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.
Keywords
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 misconception
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).
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?'
Teacher tip
Pupils will already have some familiarity with triangles but this lesson helps them to define what a triangle is. Pupils begin to classify and sort triangles by their angles, length of sides and whether they have reflective symmetry or not. The sorting provides opportunities for pupil discussion.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Which of these images shows a right angle?
Q2.A right angle is the same as a turn.
Q3.How many right angles does this shape have?
Q4.Look at this triangle. Which of these statements are true?
Q5.Which letter does not have at least one right angle?
Q6.Which shapes have at least one right angle?
Assessment exit quiz
6 Questions
Q1.The corners of a shape are called the .
Q2.Which of these shapes are triangles?
Q3.Which of these statements are true for all triangles?
Q4.Which triangle is exactly the same size and shape as shape a)?
Q5.Which triangles have one right angle?
Q6.Which triangles have at least two sides the same length?
To help you plan your 3 maths lesson on: Identify properties of triangles, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 3 maths lesson on: Identify properties of triangles, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 2 maths lessons from the Right angles unit, dive into the full primary maths curriculum, or learn more about lesson planning.