Explore, sort and classify triangles
Lesson details
Learning outcome
I can sort triangles in different ways based on their properties.
Key learning points
- 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.
Keywords
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 misconception
Children might find it difficult to create triangles with equal angles.
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.
Teacher tip
This lesson uses non-standard units of length such as matchsticks when comparing the lengths of the sides. There could be opportunities to also use standard units of measure, measuring the lengths of sides with a ruler. Pegboards are also used. All support children to construct and draw triangles.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Which of these statements describe the properties of all triangles?
Q2.True or false. The images are all triangles.
Q3.Match the different triangles to their properties.
Q4.How many equal sides and equal angles does an isosceles triangle have?
Q5.A triangle with 3 equal sides and 3 equal angles is called an __________ triangle.
Q6.How many equal sides and equal angles does a scalene triangle have?
Assessment exit quiz
6 Questions
Q1.Which of these is true for all right-angled triangles?
Q2.These triangles have been sorted. What type of triangles are in this set?
Q3.These triangles have been sorted. Which triangle has been incorrectly sorted?
Q4.True or false. Right-angled triangles can be scalene or isosceles.
Q5.Jacob has made these triangles. Match the triangle to the correct description.
Q6.This shape is a right-angled triangle.
To help you plan your 4 maths lesson on: Explore, sort and classify triangles, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 4 maths lesson on: Explore, sort and classify 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 Properties of 2D and 3D shapes and symmetry unit, dive into the full primary maths curriculum, or learn more about lesson planning.