Symmetry (introduction)

Symmetry is the key to the balance of a design or structure. What is symmetry? How does an image have symmetry? What would you have to do to be sure that an image or construction was symmetrical. In this concept, you will learn to identify lines of symmetry.

Sometimes, an image will have parts that mirror themselves within one object. This is called symmetry

Image of heart

Let's look at the image of a heart above. It has two sides that match. The heart is symmetrical because there is symmetry in its design. This heart can be divided in half vertically where one half matches the other half.

Line of symmetry

This line that divides the heart into matching parts is called the line of symmetry.

Lines of Symmetry

Look at the cross above. It has two lines of symmetry. The cross can be divided in half perfectly vertically and in half horizontally.

This means there are two lines of symmetry in the cross.

Practice Questions

What is symmetry?

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How does an image have symmetry?

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What would you have to do to be sure that your image was symmetrical?

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Does this image have symmetry?

Strategy Introduction

Does this image have symmetry? Can it be a reflection?

First, try to divide this butterfly image evenly so that one side can reflect the other. Can you draw a line of symmetry?

Line of Symmetry

The answer is yes. Therefore the image of the butterfly has symmetry.

Does this image have symmetry?

Does the image of the flower have symmetry? First, try to divide this flower evenly so that one side can reflect the other. Can you draw a line of symmetry?