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

**In this post we will be answering the question “what is a line of symmetry?” and giving you all of the information you need to help your child understand this small section of the maths curriculum! There are a few practice questions for your child to test their skills, so make sure you scroll all the way to the bottom of the blog.**

This blog is part of our series of blogs designed for parents supporting home learning and looking for home learning resources during the Covid-19 epidemic.

**What is a line of symmetry?**

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

This means that if you were to fold the shape along the line, both halves would match exactly. Equally, if you were to place a mirror along the line, the shape would remain unchanged.

A square has 4 lines of symmetry, as shown below.

An equilateral triangle has 3 lines of symmetry.

**Lines of symmetry in different symmetrical shapes**

Your child will learn all about the different shapes and their respective lines of symmetry, but here are some of the most common 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.

**Symmetrical shapes (lines of symmetry) practice questions**

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

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

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

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