Congruent Shapes

Which of these pairs of shapes are **congruent**?

To be able to answer that question correctly, we need to know what congruent means. π€

Congruent shapesare shapes that are exactly thesame shape and size.

If you put two congruent shapes on top of each other, the top one would completely cover the second one.

To test if two shapes are congruent, they need to have:

β the same shape

β the same size

Shapes should check out on these two tests to be congruent.

Here's our first pair.

Let's check if they're congruent.

(1) Are they the same shape?

They are both circles.

β
Yes, they're the **same shape**!Β

(2) Are they the same size?

One circle is big. The other one is smaller than it.

β No, they're **not the same size**.

π These shapes are **not congruent.** π΄

Here's our second pair.

Are they congruent?

Let's check!

(1) Are they the same shape?

One shape has 5 sides. The other shape has 8 sides.

β No, they're **not the same shape**.

(2) Are they the same size?

β No, they're **not the same size**.

This pair does not check out on the two tests.

π These shapes are **not congruent.** π΄

Here's another pair of shapes.

Let's check if these two shapes are congruent.

(1) Are they the same shape?

They're both triangles.

β
Yes, they're the **same shape**.

(2) Are they the same size?

β
The two triangles are the **same size**.

π These two shapes are **congruent!** π

But we see that their colors are different.

Are they still congruent?

Yes, because **color does not matter **when looking for congruence.

The triangles are congruent because they have the same shape and size.

What about these two shapes?

Are they congruent? π€

It might seem like they're not.

But let's check.

(1) Are they the same shape?

β Yes, they're both triangles. They are the same kind of triangle.

Their sides and angles are the same.

(2) Are they the same size?

It looks like they are, but we're not sure.

The purple triangle does not look exactly like the yellow triangle.

What if we **rotate it to the right**?

Like this:

Do their sizes look the same now?

β Yes, they have the same size!Β

This means that these triangles are **congruent**.

πTip:Congruent shapesmatch even if you flip, slide, or turn them.

Great job learning about congruent shapes!

Now, you can move on to practice. πͺ

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