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What is a line of symmetry: examples and guide

what is a line of symmetry

Knowing what symmetry is isn’t just useful for school: it can also help you to create aesthetically pleasing designs! In this article, you’ll learn what symmetry is and how it can be used to create beautiful artwork.

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What is a line of symmetry?

A line of symmetry is a line that splits a design in half so that both of the halves are symmetrical (look the same on both sides). 

To create a line of symmetry, you need an anchor point. This is the point where the two halves of the design meet. The anchor point can be anywhere on the line of symmetry, but it’s usually in the middle!

Want to learn even more about symmetry? Have a go at an interactive example question!


Why is symmetry helpful?

There are lots of reasons why symmetry is helpful. One of the most important is that symmetry creates balance. Our brains really like symmetrical things and are automatically drawn to it.

Another reason is that it makes things much easier to understand. Symmetrical objects are predictable, so we know what to expect, making them easier to remember.

Lastly, symmetry is aesthetically pleasing to us. We tend to find symmetrical objects attractive and harmonious. This may be because symmetry exists throughout nature and reminds us of some of our most beautiful creations in life.


How to create a line of symmetry

There are many ways to create a line of symmetry, but the most common way is by using a ruler. 

  1. First, you need to find the centre of your design. You can do this by folding a piece of paper in half and finding the crease. 
  1. Once you’ve found the centre, you can draw a line from top to bottom or from left to right, and you now have your line of symmetry!

To create a diagonal line of symmetry, you can fold the paper in half diagonally. Then, once you’ve found the centre, you can draw a line from one corner to the other: you’ve now discovered your diagonal line of symmetry! 

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Symmetry examples

Lots of shapes have lines of symmetry, but some shapes have more than others. 

For example, a square has four lines of symmetry (one horizontal, one vertical, and two diagonal). On the other hand, some shapes have no lines of symmetry. For example, a circle and oval both have no lines of symmetry, because they’re symmetrical all around their centres!

Here’s a quick guide to how many lines of symmetry the most common 2D shapes have.

How many lines of symmetry does a rectangle have?

A rectangle has two lines of symmetry: one horizontal and one vertical.

How many lines of symmetry does a square have?

A square has four lines of symmetry: one horizontal, one vertical, and two diagonal.

How many lines of symmetry does a triangle have?

A triangle has one line of symmetry: the line that bisects the triangle.

How many lines of symmetry does a parallelogram have?

A parallelogram has no lines of symmetry.

How many lines of symmetry does a pentagon have?

A pentagon has five lines of symmetry: one horizontal, one vertical, and three diagonal.

How many lines of symmetry does a hexagon have?

A hexagon has six lines of symmetry: one horizontal, one vertical, and four diagonal.

How many lines of symmetry does an octagon have?

An octagon has eight lines of symmetry: four horizontal and four vertical.

How many lines of symmetry does a circle have?

A circle has no lines of symmetry because it is symmetrical all around its centre.

How many lines of symmetry does a kite have?

A kite has one line of symmetry: one vertical.

How many lines of symmetry does a rhombus have?

A rhombus has two lines of symmetry: two diagonal


What is rotational symmetry?

Rotational symmetry is where a design repeats itself, creating a symmetrical pattern. 


How to create rotational symmetry

  1. First, find the centre of your design. You can do this by folding some paper in half and finding the crease. 
  1. Once you’ve found the centre, draw a circle around it. This will be your anchor point.
  1. Next, find the points at which you want the design to repeat itself. For example, if you’d like the design to repeat itself four times, find four central points from the anchor point. To do this, you can use a ruler to draw lines from the anchor point to the four corners of the paper.
  1. Once you’ve found the points where you’d like the design to repeat, draw lines from them to the anchor point. This will create a symmetrical pattern for you!

Symmetry activities and games

Looking for a way to explore symmetry with your pupils or child? Here are some activities and games you can enjoy in the classroom or at home:

  • Have a symmetry scavenger hunt! Look around your house or classroom and see how many objects you can find that have symmetry. Can you find any objects with more than one line of symmetry?
  • Fold a piece of paper in half, then fold it in half again. Next, draw a shape on the paper and cut it out. Now, unfold the paper and see how many lines of symmetry your shape has!
  • Cut out a shape from construction paper. Now, using a compass, draw a circle around the shape. Cut out the circle and see how many rotational symmetries your shape has.
  • Make a symmetrical design using crayons, markers or paint. You can use a ruler to help you draw the lines of symmetry. Then, use symmetry to create a repeating pattern.

A summary of symmetry 

By using the above techniques for standard and rotational symmetry, you can create your very own beautiful, symmetrical designs. 

In addition, being able to identify lines of symmetry can help you in many areas, from art to mathematics. We hope that this article has helped you learn more about lines of symmetry and given you some ideas for fun activities to explore with your children or pupils!

If you’d like to learn even more about the topic, why not try DoodleMaths? It’s filled with fun, interactive questions exploring symmetry – and best of all, you can try it for absolutely free!

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