(upbeat music) - Hey, everybody.

These fish are really similar, right?

They are both types of fish.

and we would say, yeah, they're fish, but things are similar.

They are not always the exact same, right?

These two fish have different attributes or different characteristics.

One is a bass and one is a trout and so they have some different things about them, right?

The length of them, maybe the height of them, the way they feel or the way that they look.

There's a little bit different things And you know that's true sometimes when we're talking about shapes as well.

Sometimes we think, hey, this looks very similar to another type of shape but there are certain attributes that have to be true and we call these defining attributes.

So when we talk about squares or triangles or hexagons, all these different shapes, there are things that have to be true for us to determine if they are actually that shape or if they're just something similar and in fact, we're going to look at a few today and we're going to decide are these the right shape, are they actually what it is, or is it something that is just close?

And we'll talk about the difference between a defining attribute and a non-defining attribute, so let's get to it.

You know what we need?

Our handy dandy chalkboard.

Chalkboard.

(Joel claps) (chalkboard whirs) There we go.

Okay, now we have some different shapes.

In the first one we're going to start with is let's start with a rectangle, okay?

What do we know about rectangles?

What are those defining attributes, are those defining characteristics that we know make up a rectangle?

Well, I know rectangles have to have how many sides?

Four of them, right?

They have four sides, they're straight sides, right, straight edges, and they have four corners or vertices.

Okay, so as I look at these shapes, we're going to look at these four different kind of shapes and see which ones are actually rectangles and which ones are kind of close but maybe not the exact same.

Let's start with number one.

Number one has straight edges, right?

We're good there.

It has four of them, four sides and it has four corners.

They come at a right angle.

A right angle, we see those a lot in different shapes.

Squares and rectangles both have those.

They make this corner right here and so that's the vertices right on these.

So there are four vertices.

Number one meets the defining attributes of a rectangle.

Now let's look at number two.

Number two is also looking kind of like a rectangle, right?

It has four sides, straight edges, four vertices.

I think these are four right angles, so it is also a rectangle, but number one and number two don't look the same, right?

That is because they have different non-defining attributes.

One of those non defining attributes is size.

So the size actually doesn't matter when we're defining what a shape might be.

We might have a really large rectangle and a really small rectangle who can both be rectangles.

So size is one of those.

Color is another one.

So they might be different colors, but that still doesn't mean that it can't be a rectangle.

That's a non defining attribute.

So now let's move to number three.

Number three has some straight edges, right, but how many vertices does it have?

If I count those up, I see one, two, three, four, five.

So it has five vertices.

That means it cannot be a rectangle because that is a defining attribute of a rectangle is that it has four vertices.

So since it has five and five sides, that's actually a pentagon.

Okay, now let's look at number four, our last rectangular type shape and what do you notice about number four?

There's something that's goin' on here.

It's not a closed shape and since those line segments don't come together, it can't be a rectangle.

A rectangle has to be a closed shape, so even though it looks very similar to one, it can't meet those same criteria or characteristics that a rectangle needs.

Let's move to a few different shapes.

Okay, now we have three more, but this time, what kind of shapes do you think we're looking at here?

These are triangles.

Now what makes a triangle?

It's different than a rectangle because triangles only have three sides.

So we have three edges, right, and we also have three vertices.

So this shape A here is a triangle.

It meets that criteria.

Now look at shape B.

Shape B, it looks different than shape A but does it still meet the defining characteristics of a triangle?

I see three sides.

I see three vertices.

It does.

So A and B can both be triangles, but let's look at shape C. Now shape C's a little bit different because it looks like a triangular type shape, but those round edges mean that it cannot be a triangle.

It has to come to a point and meet at that vertices.

So thanks for joining me.

I know these are a little tricky, but great job learning with me today.

(upbeat music)