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In this video, let's discuss what we mean with polygons.

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All right, let's take an example of a polygon.

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This is a five sided polygon, which we call the Pentagon.

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Now, let's try to understand what we mean with polygons.

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And let's also try to visualize the definition using this example over here.

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All right.

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The polygon is a simple closed figure.

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All right.

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What does that mean?

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It's simple.

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That means it does not cross itself.

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For example, if you have a shape like this, this is not a polygon because you can see over here that

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it crosses itself at this point.

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Right.

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So polygons do not cross themselves.

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And it is a closed figure.

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That means it's not open.

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But this over here is an example of an open shape.

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Right.

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The polygons have to be closed.

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Also, polygons have to be made up of entirely line segments.

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So if you have a shape like this.

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This is not a polygon, right, but whenever you have the word polygon in a question, you can be sure

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that the whole shape is made up of nine segments.

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All right, let's move on.

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Let's try to get familiar with some common polygons.

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So we have seen that polygons are made up of entirely line segments.

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But let's see if a polygon has five nine segments.

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That's what we call a Pentagon.

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All right, now, if it has four line segments, that's what we call a quadrilateral.

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All right, and if it has three lines, we get a triangle.

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And what do you think can be made with just two lines?

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No, you cannot form a polygon with two lines.

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You need a minimum of three line segments to form a polygon.

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All right.

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Now let's move on.

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Let's see how to name a polygon.

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Let's take an example.

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We have this Pentagon over here.

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Let's name these.

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What is this as abcde e.

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So that's A, B, C, D, E, all right, now I can call this polygon as polygon, a, b, c, d, e,

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you can see that the corners are taken in order.

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So I can call this as A, B, C, D, E, or I could even call it s e e, b, c, b right.

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Now, what is a way in which it cannot be named.

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You cannot call it as a c e right.

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That's E over here and then you have C you cannot go from E to see when you're naming it.

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It has to be taken in order.

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You could start from any point.

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So you can also call this as an e e, b, C, that is fine because you're going in this, this dictionary,

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but you have to take the vertices in a particular order.