Geometry
 Is a branch of mathematics concerned with questions of shape, size, relative position of figures, and the properties of space.

The basics concepts of geography are:

-Point
 A point has no length, width, or height - it just specifies an exact location. It is zero-dimensional.
Every point needs a name. To name a point, we can use a single capital letter. The following is a diagram of points A, B, and M:

-Line
A line is as wide as a point, infinitely thin, having an infinite number of points, (in a straight row), extending forever in both the directions. Any two lines can intersect at only a single point.

-Line Segments
A line segment, or segment, is a part of a line, which has two endpoints. The endpoints give the line segment a fixed, or finite length.

-Ray
A ray is a line segment that has only one endpoint. A ray is infinite in one direction. That means that it goes on forever in one direction. 

-Midpoints
The midpoint of a segment divides the segment into two segments of equal length. 
The midpoint will be in the middle of A and B. Since M means midpoint.

-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.
All the points and lines that lie on the same plane are said to be coplanar.

-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.

-Angles
An angle  is a figure by two rays with a common endpoint, and which are not in the same  point.