CBSE Class 9 Answered

It is called Playfair's Axiom which states that ''Through a given point, not on the line, one and only one line can be drawn parallel to a given line.''

That is, if P is a point not lying on the line l, then there exist a line m which is parallel to line l which is unique.

This means that we cannot have another line, say n, which is parallel to line l passing through the same point, P as shown below. Only one line can be parallel to a given line passing through a particular point not on the line.