What does a child have to do to identify line symmetry in the 11+?

Identify or complete a reflection across one mirror line. It is one of 55 named maths skills in the 11+, in the geometry strand, and this page carries 1 interactive exercise that practises it.

What is the trap in an 11+ identify line symmetry question?

A shape can turn onto itself without having any fold line, so the two counts are not always equal. The wrong answers on this skill are built out of that, not out of random numbers, so it is worth naming out loud before your child meets it under time pressure.

What can I say if my child is stuck on identify line symmetry?

Point at the next move rather than explaining the whole rule. Imagine folding the shape in half so one side lands exactly on the other; count every fold that works.

What is not part of identify line symmetry in the 11+?

The skill map draws the line here: Excludes rotational symmetry. A question past that line is testing a different named maths skill, which is worth knowing before you spend a week practising the wrong one.

Which other 11+ skills should we practise alongside identify line symmetry?

The geometry strand holds 15 skills that are placed together on the skill map, and the pages next to identify line symmetry are identify a geometric transformation, plot or read a coordinate and preserve measure under a rigid transformation. Each has its own exercise and its own link, and none of them needs an account.

How can my child practise identify line symmetry for free?

Use Symmetry Painter, embedded on this page. It is the exercise the skill map attaches to identify line symmetry, it runs in the browser with no account to make, these exercises are not scored and do not save learner records. The separate quiz sends answers for marking and shows a score, without saving an assessment record. It also has its own link, so you can send it to a child without sending them anywhere else first.

Maths · Geometry

Identify line symmetry

Identify or complete a reflection across one mirror line.

Watch the worked example

Crack the Mirror Test

This video shows how to find a line of symmetry or complete the reflected half of a shape. Watch an 11+ maths question solved step by step.

Open video page and transcript

Keep practising with Smart Cub Learning. Find topics to practise next

Quick quiz: Identify line symmetry

10 questions, with feedback after each one. No sign-up needed.

Read the questions in this quiz

Question 1
What is the order of rotational symmetry of this shape?
- A.6
- B.1
- C.2
- D.0
Question 2
How many lines of symmetry does this shape have?
- A.1
- B.2
- C.8
- D.4
Question 3
How many lines of symmetry does this shape have?
- A.8
- B.5
- C.0
- D.6
Question 4
What is the order of rotational symmetry of this shape?
- A.4
- B.5
- C.0
- D.2
Question 5
What is the order of rotational symmetry of this shape?
- A.4
- B.0
- C.5
- D.6
Question 6
What is the order of rotational symmetry of this shape?
- A.6
- B.5
- C.0
- D.3
Question 7
What is the order of rotational symmetry of this shape?
- A.0
- B.2
- C.5
- D.3
Question 8
How many lines of symmetry does this shape have?
- A.4
- B.1
- C.0
- D.9
Question 9
What is the order of rotational symmetry of this shape?
- A.1
- B.5
- C.4
- D.0
Question 10
How many lines of symmetry does this shape have?
- A.6
- B.7
- C.8
- D.3

Practise it now

Half a rocket is painted. Paint the other half so the mirror line splits it perfectly.

This exercise practises identify line symmetry alongside its own main skill, Symmetry & Reflection.

Loading the interactive exercise. Nothing you do here is saved or scored.

A worked example

One question of the kind this skill is tested with, worked all the way through: the reasoning, and what the wrong answers are there to catch.

Finding the lines of symmetry

Worked example: How many lines of symmetry does this shape have?

Imagine folding this three-pointed star through its centre. A fold only counts when every corner and edge lands exactly on another one.

Answer: 3

How you get there

Test every fold through the centre of a three-pointed star. There are exactly 3 successful folds, and they pair every corner and edge with a matching corner or edge on the other side; every other fold leaves part of the outline unmatched. Each successful fold is one line of symmetry, so the answer is 3.

Why the other answers tempt

A shape can turn onto itself without having any fold line, so the two counts are not always equal.

If they are stuck, say this

Imagine folding the shape in half so one side lands exactly on the other; count every fold that works.

Now do it live in Symmetry Painter

Kitchen-table script for parents

Try this together

A friendly mini script for the breakfast table, school run or a quiet two minutes. Read it aloud as written, or make it your own.

Ready? Let's have a go at Identify line symmetry together. Take a look at the picture. Here is what matters: Imagine folding this three-pointed star through its centre. Here comes the question: Worked example: How many lines of symmetry does this shape have? Before we race ahead, let us choose one good first step. Here is a helpful clue: Imagine folding the shape in half so one side lands exactly on the other; count every fold that works. Nice work. Now let us follow the thinking: There are exactly 3 successful folds, and they pair every corner and edge with a matching corner or edge on the other side; every other fold leaves part of the outline unmatched. So our answer is: 3. There is one sneaky trap to watch for: A shape can turn onto itself without having any fold line, so the two counts are not always equal. Can you show me that first move again in your own words? Brilliant. No rush; we are practising a method you can reuse, not trying to win a speed contest.

What this exercise is doing

Symmetry Painter

Half a rocket is painted. Paint the other half so the mirror line splits it perfectly.

This engine’s own main skill is Symmetry & Reflection. It practises identify line symmetry alongside it.

Reflecting across a vertical mirror keeps every row exactly where it is and only flips the columns: a square three steps left of the mirror lands three steps right of it. That is why the rocket keeps its height but swaps its sides. Distance to the mirror never changes - only the direction does.

What to say if they get stuck

A reflection is not a slide. The cell nearest the mirror on the left maps to the cell nearest the mirror on the right.
Work one row at a time. Count how many squares that row sits from the mirror, then count the same number out the other side.
Press and hold the mirror line - it will show you the reflection for a moment.

Open Symmetry Painter on its own page to share it

How identify line symmetry differs from the skills beside it

The same exercise practises one other skill, and telling them apart is often the difficulty rather than the exercise itself. On this page the skill is: identify or complete a reflection across one mirror line, and it stops where excludes rotational symmetry.

Reflect a visual figure
Track all marked parts through one reflection. No rotation or attribute change.

Related maths skills

Classify an angleClassify one angle by size or compare it with a reference turn.
Compose coordinate transformationsApply two stated coordinate transformations in order.
Identify a cube netDetermine whether a net folds to a cube.
Identify a shape propertyIdentify one stated property of a 2D or 3D shape.
Identify a geometric transformationIdentify the translation, rotation, or reflection relating a shape and its image.
Plot or read a coordinateRead or place one point on a coordinate grid.
Preserve measure under a rigid transformationUse the fact that translation, rotation, and reflection preserve lengths and angles.
Reflect a coordinateDetermine a point image after reflection in a stated coordinate axis.
Reflect a shapeIdentify the result of one reflection in a stated mirror line.
Rotate a coordinateDetermine a point image after a stated rotation about the origin.
Rotate a shapeIdentify the result of one stated rotation.
Solve an angle relationCalculate one unknown angle using a stated line, point, triangle, or quadrilateral relation.

All maths 11+ skills

Questions parents ask about identify line symmetry

What this skill involves, common mistakes and ways to practise it at home.

: Identify or complete a reflection across one mirror line. It is one of 55 named maths skills in the 11+, in the geometry strand, and this page carries 1 interactive exercise that practises it.
: A shape can turn onto itself without having any fold line, so the two counts are not always equal. The wrong answers on this skill are built out of that, not out of random numbers, so it is worth naming out loud before your child meets it under time pressure.
: Point at the next move rather than explaining the whole rule. Imagine folding the shape in half so one side lands exactly on the other; count every fold that works.
: The skill map draws the line here: Excludes rotational symmetry. A question past that line is testing a different named maths skill, which is worth knowing before you spend a week practising the wrong one.
: The geometry strand holds 15 skills that are placed together on the skill map, and the pages next to identify line symmetry are identify a geometric transformation, plot or read a coordinate and preserve measure under a rigid transformation. Each has its own exercise and its own link, and none of them needs an account.
: Use Symmetry Painter, embedded on this page. It is the exercise the skill map attaches to identify line symmetry, it runs in the browser with no account to make, these exercises are not scored and do not save learner records. The separate quiz sends answers for marking and shows a score, without saving an assessment record. It also has its own link, so you can send it to a child without sending them anywhere else first.

Knowing which maths topic to practise is most of the work

A free diagnostic covers arithmetic, fractions, geometry, measure and data handling, and comes back with the topics to spend the next few weeks on.