In geometry a line:

A line has no ends !

Play With It

Change the position of points A and B. Note that the line AB extends forever in both directions:

Line Segment

line segment
When it does have ends it is called a "Line Segment".


When it has just one end it is called a "Ray"

This is Cool

Now play with this one ... point "C" is made to always be an equal distance from point "A" and "B". The result is a line (all the possible position of point "C" make a line):



Point, Line, Plane and Solid

A Point has no dimensions, only position
A Line is one-dimensional
A Plane is two dimensional (2D)
A Solid is three-dimensional (3D)