Line, Line Segment, Ray

 

POINT

In geometry a point is represented by a dot. It has no size i.e. no width, no length and no depth. It just denotes a location.

LINE

A line is defined as a line of points that extends infinitely in two directions. It has one dimension, length. It is defined by two points and written as shown below with an arrowhead

COLLINEAR POINTS

Points that are on the same line are called collinear points.

  • Two lines that meet at a point are called intersecting lines.

A line segment is the segment between A and B as shown below.

 A space extends infinitely in all directions and is a set of all points in three dimensions. 

Consider an example of a box. Now you can imagine in the space inside the box.

RAY:

Ray, is a line with an endpoint that extends infinitely in one direction.  One of the most obvious examples is a sun's ray of light in space.