A line is a superficial figure with no density and can be extended in both directions. Mostly, it is called straight line only to highlight that there are no arcs anywhere in it. In a figure, PQ and QR are two lines merging at a tip Q ; the tip Q is called as vertex. The gap between two lines highlighted as Q is called an angle. Line segment refers to the part of line which has two end points. Line segment PQ is indicated by PQ. Ray refers to a part of the line which a single end point