Reflect polygons in a line of symmetry
Lesson details
Learning outcome
I can reflect polygons in a line of symmetry, including when there are no sides parallel to the line of symmetry.
Key learning points
- When you reflect a shape, it will be the same distance from the mirror line on both sides.
- You can reflect a shape by counting the position of each vertex and making a mark, and then joining the marks.
Keywords
Line of symmetry - If you were to fold a shape on its line of symmetry, both halves would match exactly.
Mirror line - Another term for a line of symmetry. If you were to fold a shape on its line of symmetry, both halves would match exactly.
Reflect - When you reflect a shape, you flip it over a mirror line or line of symmetry without turning it or changing the size.
Reflection - The mirror image of a shape.
Common misconception
Children may translate or copy a shape rather than 'flipping it' over the line of symmetry.
Use mirrors to support children's understanding of how a shape flips when it is reflected. Explore this idea with a wide variety of shapes.
Teacher tip
Although children are taught different strategies to reflect shapes in this lesson, they may benefit from using a mirror to support their understanding of reflective symmetry.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Which of these shapes are regular polygons?
Q2.An equilateral triangle has ___ lines of symmetry.
Q3.This shape is a regular pentagon. It has lines of symmetry.
Q4.The number of lines of symmetry in a __________ is equal to the number of sides.
Q5.True or false. An isosceles triangle has 3 lines of symmetry.
Q6.Which statement is true?
Assessment exit quiz
6 Questions
Q1.The mirror image of a shape is a __________ of it.
Q2.Which image shows a reflection?
Q3.True or false. This image shows a reflection.
Q4.Which image shows a reflection?
Q5.Sam is using vertices to reflect this shape. Which vertex has been placed in the wrong position on the grid?
Q6.Complete the sentence. This image does not show a reflection because __________.
To help you plan your 4 maths lesson on: Reflect polygons in a line of symmetry, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 4 maths lesson on: Reflect polygons in a line of symmetry, 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.