In this video, let's discuss some more basic terms related to a polygon, so we take our Pentagon as
an example.
Let's name the corners as ABCDE.
Now, the sides of the polygon are these nine segments, right?
So we have five line segments.
ABC could be.
And you can notice that if you have five, what he says.
So that's the next item.
But what is this?
Are these corners, right?
That's A, B, C, D and E.
Now, if you have five, what is this?
Then you will have five sites.
Right.
So if you have for dessert, you will have four sites.
All right, now, what are decent sites of a polygon?
These are sites with a common end point.
Let's take an example.
You have site Abe over here and you have over here.
You can see that point B or Vertex B is a common endpoint of these two sites right there for Abe and
B.C. are just in sites.
All right.
Now, what about Atcheson?
What is this?
These are endpoints of the same site.
For example, if you take site Ebbie, you can see that A and B are in points off site.
Right.
Therefore, point and point we are at just in what is now you know, that Anderssen means something
that's next to each other, to adjacent sites are sites that are next to each other.
Similarly are decent vertices, advertisers that are next to each other.
All right.
Now, the last item that we are going to visit over here is diagonals.
Now, if you join two known Addison vertices, you will get a diagonal.
Let's take one of the signals that you can get over here.
If you join E and C, you get A diagonal, you join E and B, you get a diagonal.
Right, because these are all known, Anderson.
What is this?
Now, if you join two, Addison, what is this one example?
And B, that is A side and that's not a diagonal.
All right.
Now, what are the diagonals over here, the diagonals are 80, right, that's 80.
Then you have AC, you have Ebbie, you have E, C, and you have DBI.
So that's five diagonals that you're getting over here.
Now, let's quickly revise the concept that we learned in permutation and combination if it's given
that you have five vertices.
So that's the case over here because it's a Pentagon.
How many diagonals can you form to the number of diagonals of an inside?
And polygon is equal to INSEE to minus in NC two is the number of ways in which you can select two points
from endpoints and you have to subtract N because you will have insights.
Right.
So you have five points over here.
If you select two points from five points, that would be five C two.
But in this case you will also get a decent what is the selected right.
And those are sides.
So you need to subtract that out.
So in this case, you will have five sites, or if you have invertors, you will have insights.
But the number of diagonals over here is five C to minus five, five C two is five in the four by two.
Right.
Which is equal to ten and ten minus five will give you a five, which is what we have got over here.