 Hi and welcome to the session. Today we will learn about ruler and compasses construction. So let us start with construction of a circle when its radius is known. So here as the first step open your compasses required radius. Now as the second step mark your point O as center like this. Next place the pointer on compasses at point O and then on the compasses to draw the circle. So this is our required circle with the given radius. Now let us learn the construction of a line segment of a given length. For this first of all draw a line L of any length like this. Now mark a point on line L. So here we have a point A on line N. As the third step open your compasses given length. Now place the pointer at point A to get the point V. So here at point A we will place the pointer of the compass and we will cut it out to get the point V. Thus A V is the required line segment of the given length. Now lastly we will learn the construction of a copy of a given line segment. In this construction we are given a line segment A B this one and we need to construct the copy of the given line segment. So open your compasses and place the pointer of compasses at point A and the pencil at point V. So here with the compasses we have measured the length of the line segment A B. Now as the third step draw a line L and mark a point on it. So here is the line L and this is the point C on line L. Now without changing the compasses settings place the pointer of the compasses at point C over here. After this draw an R to cut line L at point. So this is the point D. Thus line segment C D is a copy of line segment A B. We finish this session. Hope you must have understood all the concepts. Goodbye, take care and keep smiling.