 Hello and welcome to the session. In this session, we will learn about planes and their properties. The floor of the room, the top of the desk of a paper, all these are examples of planes or now we will learn about the definition of a plane and that is extends indefinitely in all directions any thickness. Now in this diagram, plane P contains the points A, B and C. plane P is extending indefinitely in all directions and it doesn't have any thickness. And now we have properties of lines in a plane. Now you can see here that on the plane A, B, C, D there can be unlimited number of lines passing through the point O. Second property is a plane A, B, C, D in segment P, Q can be drawn. No other line segment can be drawn through these three points in this plane. And the next property is in a plane at one point the planes A, B, C, D and P, Q, R, S. Now you can observe here that two lines in a plane can either intersect each other at a properties. Now here for this on the flat surface that is plane of a book, the table property is the plane A, B, C, D and P, Q, R, S are intersecting planes. So the line C, D which is shown in the figure is the line of the intersection. Now let us see an example for this a book and vertically a table top the plane intersecting this section you have learned about planes and their properties.