Symmetry

Does this shape have **symmetry**?

Before we answer that question, let's review what symmetry is.

Shapes have **symmetry** when you can draw a line that will divide them into two **equal **parts.

We call this line the **line of symmetry**.Β

When we fold along the line of symmetry, both parts will exactly be the same.Β

Let's try to draw a line of symmetry on this octagon.

What can you say about the two parts?

That's right! The part on the left of the line is the same as the part on the right. π

β This shape has symmetry.

Pictures with symmetry are described as **symmetrical**.** **

Not all pictures and shapes are symmetrical.

For example, look at this shape:

When we fold the triangle along the red line, the two parts are not equal. β

But we can try drawing another line.

The two parts still do not match. β

Let's draw another line.

The parts still don't match. β

No matter where we try to draw a line, the two parts don't match.Β

This triangle has no** line of symmetry**, so it's not **symmetrical**.

Can you tell if this picture has **symmetry**?

Let's find out by drawing lines on it. π

We can draw a vertical line.

Is this a line of symmetry?

It is! Both sides match exactly. β

We can draw another line from left to right.

The part above the line matches the part under it.Β

So, this horizontal line is also a line of symmetry. β

Now, let's try drawing a diagonal line.

Did you notice something?

Yes! The parts on both sides of the line still match. β

This picture has more than one** ****line of symmetry**.** **

It is definitely symmetrical! π

A picture or shape can have more than 1 line of symmetry, but it only needs **1 line of symmetry** to be **symmetrical**.

Now, how many lines of symmetry does this shape have?

We see that the vertical line is a line of symmetry. β

Do you think there are more?

We can try to draw a horizontal line.

It's not a line a of symmetry. β

Let's try a diagonal line like this:

Is it a line of symmetry?

Yes! β

This shape has 5 lines of symmetry.Β

It is symmetrical. π

Good job! π Now, you can move on to practice!

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