Students, welcome to geometry in this video.
Let's discuss a few basic concepts in geometry.
We start with points to understand points.
Let's draw a few points.
All right, so I'm marking four points over here, you can see that they don't have linked or bread,
but they are just dots.
All right, but what do we use points for?
They are used to determine and location.
For example, let's take a rectangle and a circle over here.
Now, this point over here is a corner of this rectangle.
Similarly, this point over here is the center of this circle.
So you can see that these points were used to determine some kind of a location.
All right.
Now, over here, we marked four points now.
Points are denoted or colored using capital letters.
So let me name these points over here as A, B, C and D now because we got familiar with points.
Let's move on to line segments.
Let's take two points, so we have point A and point B over here.
Now let's mark a few ways in which someone could travel from A to B.
All right, so these are four ways in which somebody could travel from A to B, another way in which
somebody could travel from A to B is this way.
Right.
And this is what we call nine segment.
Maybe an important thing to note is that it's the shortest route from A to B, and that's what we define
a line segment now or here we have nine segment.
Maybe it's denoted as a B with a BA on top of it and B is also the same thing.
And in many questions you will see that AB is just denoted as a B.
Now over here you can see that this line segment over here as two end points, right.
Pointy end point B are in points of this line segment.
So it does not extend beyond point and point.
B, let's move on two lines.
So we have seen points and line segments.
Let's move on to what we call a line.
Let's draw an example of a line over here, we have Nine Ebbitt now, an interesting thing to note in
this case is that there are two arrows on both the sides.
Right.
What does that mean?
It means that this extends indefinitely towards both sides.
So I can keep drawing it like this.
It would be the same line to a line extends indefinitely in both directions.
That is in contrast to a line segment.
A line does not have endpoints.
All right.
So that's why we have these two arrows over here.
Now, we do not align as a B with the bar on top of it.
And it has two arrows, right?
Because it indicates that it extends on both directions.
Now, an important thing about the line is that two points are enough to determine a line.
So you just need two points.
Now, for example, if you have point B and point Q over here.
All right.
So you can only draw one line through B and Q, and this is the line that can be drawn through.
Q You can see that there is no other line that can be drawn apart from the line that we have already
drawn.
Now over here, another interesting point is that I have taken to other points.
I'm taking points over here and point B over here you can see that nine P, Q and line cream is the
same line because the line is not limited to the space between the two points.
It extends indefinitely in both directions.
So these two lines are the same line.
Now we have seen that lines can be denoted with a bar on top of it with arrows on both sides like what
we have seen over here.
Another way in which a line can be denoted is using small letters.
For example, you will see questions where letters like L and M are used to denote a line.
So, for example, I have this line over here.
I can denote it with the letter M.