Teaching support from the UK’s largest provider of in-school maths tuition

blogs read

blogs read

resources downloaded

resources downloaded

one to one lessons

one to one lessons

schools supported

schools supported

Deepen mathematical understanding

396 mastery-aligned teaching units designed to plug individual gaps and delivered by specialist tutors

Preview lessons

Hundreds of FREE online maths resources!

Daily activities, ready-to-go lesson slides, SATs revision packs, video CPD and more!

Deepen mathematical understanding

396 mastery-aligned teaching units designed to plug individual gaps and delivered by specialist tutors

Preview lessons

What Is A Line Of Symmetry: Symmetrical Shapes Explained For Primary School

To help your child understand this part of the maths curriculum, this guide helps explain what a line of symmetry is and provides a few practice questions to test their skills.

This blog is part of our series of blogs designed for parents, teachers and carers supporting home learning and looking for home learning resources during the Covid-19 epidemic and beyond. But can be used for children of primary school age at any point of their journey into symmetry and mathematics.

What is a line of symmetry?

A line of symmetry is a line that cuts a shape exactly in half.  

In symmetrical shapes, like a regular polygon, this means that if you were to fold the shape along the line of symmetry, both halves would match exactly and be mirror images of each other. If you were to place a mirror along this line, the shape would remain unchanged.

However, shapes and objects that do not have two identical halves when divided with a line of symmetry are called asymmetrical figures.

A Third Space Learning online lesson exploring reflecting shapes in a line of symmetry.
A Third Space Learning online lesson exploring reflecting shapes in a line of symmetry.

Lines of symmetry in different symmetrical shapes

Each shape has a different number of lines of symmetry, whether it’s a quadrilateral rhombus or parallelogram, a scalene triangle or isosceles triangle, your child should understand that each shape has different lines of symmetry. For example,

For example, a square has 4 lines of symmetry, as shown below.

Lines of symmetry in a square

While an equilateral triangle has 3 lines of symmetry.

Lines of symmetry in a triangle
FREE 2D Shapes With Symmetry Worksheet Year 3

FREE 2D Shapes With Symmetry Worksheet Year 3

Download this FREE recognising 2D shapes Geometry worksheet for Year 3 pupils, from our Independent Recap collection.

Number Of Lines Of Symmetry

As well as having different numbers of lines that split the shape into identical parts, these lines can also be in different positions.

Each symmetrical shape also has a different axis of symmetry. For example, a heptagon has 7 angles each with a diagonal line of symmetry. While a hexagon has 1 horizontal line of symmetry, 1 vertical line of symmetry, and 4 diagonal lines of symmetry.

So there are different types of lines of symmetry depending on the shape.

Lines of symmetry in different shapes

When will my child learn about lines of symmetry in primary school?

Children are introduced to symmetry in Year 2, where they should be taught to identify and describe the properties of 2-D shapes, including the number of sides and line symmetry in a vertical line. 

This is then developed in Year 4, where pupils will identify lines of symmetry in 2-D shapes presented in different orientations and complete a simple symmetric figure with respect to a specific line of symmetry. 

The non-statutory guidance also recommends that children recognise line symmetry in a variety of diagrams, including where the line of symmetry does not dissect the original shape.

Line of symmetry examples and practice questions

To practice lines of reflection symmetry, you can draw an imaginary line or mirror line onto different shapes. Or you can use practice questions like:

1)  Here is a shape on a grid. Complete the design so that it is symmetrical about the mirror line. Use a ruler.

Line of symmetry KS2 question

2) These two shapes are made from equilateral triangles. Draw one line of symmetry on each shape. Use a ruler.

Line of symmetry question for children

3) Here is a grid with eight squares shaded in. Shade in two more squares to make a symmetrical pattern.

Line of symmetry question

4) The letter D has a line of symmetry. Tick all the other letters that have a line of symmetry.

Line of symmetry primary school maths

Wondering how to explain other key maths vocabulary to your children? Check out our Primary Maths Dictionary For Kids. You can also check out our similar blogs:

Do you have pupils who need extra support in maths?
Every week Third Space Learning’s maths specialist tutors support thousands of pupils across hundreds of schools with weekly online 1-to-1 lessons and maths interventions designed to plug gaps and boost progress.

Since 2013 we’ve helped over 150,000 primary and secondary school pupils become more confident, able mathematicians. Learn more or request a personalised quote for your school to speak to us about your school’s needs and how we can help.

Primary school tuition targeted to the needs of each child and closely following the National Curriculum.

Ellie Williams
Ellie Williams
Third Space Learning
Content Team
With a love for all things KS2 maths, Ellie is a part of the content team that helps all of the Third Space Learning blogs and resources reach teachers!
x
FREE 2D Shapes With Symmetry Worksheet Year 3

FREE 2D Shapes With Symmetry Worksheet Year 3

Download this FREE recognising 2D shapes Geometry worksheet for Year 3 pupils, from our Independent Recap collection.

Sign Up Now!

FREE 2D Shapes With Symmetry Worksheet Year 3

Downloadable resource

Download this FREE recognising 2D shapes Geometry worksheet for Year 3 pupils, from our Independent Recap collection.

Sign Up Now!
x

FREE Let’s Practise Telling The Time Activity Sheets (KS1 & KS2)

Secure and embed key time concepts such as: o’ clock, half past, quarter past, and the position of the minute hand.

Ideal for pupils who struggle to tie together the multiple concepts required to effectively tell the time.

Download free