 Hi, and welcome to the session. Today we will learn basic geometrical ideas. First of all, let us start with points. By a sharp tip of the pencil, mark a dot on the paper like this. This is known as a point, a point. Determine location. They are denoted by a single capital letter like A, V, X, etc. So here, let us denote this point by the capital letter A. Now, this is read as point A. Next, we have a line segment on the sheet of a paper. Then, the shortest distance between the points is the line segment A to B. So, this is the line segment from A to B and it is denoted by line segment A, V or line segment B, A. Also, the points A and V are known as the end points of line segment A, V. Now, let us move on to line like this and this line is denoted by A, V. We can also denote it by a small letter, etc. See, this is line A but they are intersecting lines and they read at a point but intersecting lines. So, that means they do not mean line N is parallel to line M. And we write it as line N is parallel to line A. What is a ray? A portion of a line in a direction. For example, this is a ray. This starts at the point A. This is called the starting point and goes endlessly in this direction. Suppose we mark a point B over here, then this ray is denoted by ray A, V. The pencil may be called these both are the examples of curves as they do not cross itself. At this point, it is said to be open. This is an open curve and this is a closed curve. There are three parts, interior inside of the curve. So, here in this closed curve, this shaded region is the interior of this curve. So, we can say here this point A is in the interior of the curve. Second part is boundary of the curve or on the curves is the boundary of the curve. So, the point B is on the boundary of this curve. And the third part is exterior is the exterior part of this curve. So, we can say that the point C is in the exterior of the curve. The interior of a curve together with its boundary region. With this, we've finished this session. Hope you must have understood all the concepts. Goodbye, take care and have a nice day.