12-11-09 --> Math Concept

Points - We may think of a point as a "dot" on a piece of paper or the pinpoint on a board. In geometry we usually identify this point with a number or letter. A point has no length, width, or height - it just specifies an exact location. It is zero-dimensional.

Lines - A line is one-dimensional. That is, a line has length, but no width or height. In geometry, a line extends forever in both directions. A line is uniquely determined by two points.

Line segments - A line segment connects two endpoints. A line segment with two endpoints A and B is denoted by . A line segment can also be drawn as part of a line.

Midpoint - The midpoint of a segment divides the segment into two segments of equal length. The diagram below shows the midpoint M of the line segment . Since M is the midpoint, we know that the lengths AM = MB.

Rays - A ray starts from one endpoint and extends forever in one direction.
A ray starting from point A and passing through Bis denoted by

Planes - Planes are two-dimensional. A plane has length and width, but no height, and extends infinitely on all sides. Planes are thought of as flat surfaces, like a tabletop. A plane is made up of an infinite amount of lines. Two-dimensional figures are called plane figures.

Space - Space is the set of all points in the three dimensions - length, width and height. It is made up of an infinite number of planes. Figures in space are called solids.
Figures in space