In geometry a line:

  • is straight (no curves),
  • has no thickness, and
  • extends in both directions without end (infinitely).

A line has no ends!

Play With It

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

Line Segment

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


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

This is Cool

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