 # 9.06 Symmetry

Lesson

## Symmetry in different environments

Do you know what happens when we reflect a shape? The shape is mirrored across a fold or axis.

Can you see any symmetrical objects around you? Let's take a look at how we can check if a shape or object is symmetrical.

### Examples

#### Example 1

Which image has the line of symmetry drawn correctly?

A
B
C
Worked Solution
Create a strategy

Choose the option that has been split into two identical halves that are the mirror image of each other.

Apply the idea

Only in option A can the shape be folded along the dashed line and lie on top of itself.

Idea summary

A line of symmetry splits an object into two identical halves that are the mirror image of each other.

## The line of symmetry

This video takes a look at the line of symmetry, also called the axis of symmetry.

### Examples

#### Example 2

How many lines of symmetry does this painting have?

Worked Solution
Create a strategy

Think of how many different lines can be drawn to split an object into two identical halves.

Apply the idea

Here is one of the lines of symmetry.

Lines of symmetry can also be drawn horizontally, vertically, and diagonally the other way.

So there are 4 lines of symmetry.

Idea summary

If a shape is symmetrical, it means that when we draw a line through it, one side is identical to the other.

Some shapes or objects have more than one line of symmetry.

### Outcomes

#### MA2-15MG

manipulates, identifies and sketches two-dimensional shapes, including special quadrilaterals, and describes their features