Parallel Lines

(b)     Parallel Lines : If two or more lines do not meet each other however far they are extended, then they are called paralle lines.  

(c)     Collinear Points : Three or more points in a plane are said to be collinear if they all lie on the same line. 
In Fig, points A, B, C and D are collinear because only one line l passes through all of them.

If the points do not lie on a line, they are called non-collinear points. 

Ex     In Fig. name :                            
        (i)     Four non-collinear points.
        (ii)     Point of intersection of the lines l and m. 
        (iii)     Point of intersection of the lines r and n. 
        (iv)     Point of intersection of the lines q and n.
        (v)     Point of intersection of the lines p and q. 
        (vi)     Four line segments. 
        (vii)     Two points on the line q. 

Sol.     (i)  A, B, C, D         (ii) B        (iii) D         (iv) C         (v) A