A point in geometry is a location. It has no size i.e. no width,
no length and no depth. A point is shown by a dot.
A line is defined as a line of points that extends infinitely in
two directions. It has one dimension, length. Points that are on
the same line are called collinear points.
A line is defined by two points and is written as shown below
with an arrowhead.
Two lines that meet in a point are called intersecting
lines.
A part of a line that has defined endpoints is called a line
segment. A line segment as the segment between A and B above
is written as:
A plane extends infinitely in two dimensions. It has no
thickness. An example of a plane is a coordinate plane. A plane is
named by three points in the plane that are not on the same line.
Here below we see the plane ABC.
A space extends infinitely in all directions and is a set of all
points in three dimensions. You can think of a space as the inside
of a box.
Video lesson: Plot a pint, a line, a line
segment and an angle in a coordinate plane.