Point
A point specifies only location; it has no length, width, or depth. We usually represent a point with a dot on paper, but the dot we make has some dimension, while a true point has dimension 0.
Line
A line has only one dimension: length. It continues forever in two directions (so it has infinite length), but it has no width at all. A line connects two points via the shortest path, and then continues on in both directions.
Plane
A plane is a flat, two-dimensional object. We often represent a plane by a piece of paper, a blackboard, or the top of a desk. In fact, none of these is actually a plane, because a plane must continue infinitely in all directions and have no thickness at
Collinear
Points if they lie on the same line.
Non-Colliner
Points if they do not lie on the same line.
Coplanar
Points if they lie on the same plane.
Non-Coplanar
Points if they do not lie on the same plane.
Space
The boundless three-dimensional extent in which objects and events have relative position and direction.
Segment
A part of a line that has two distinct end-points and continues for a distinct distance.
Betweenness of Points
A point is between two other points on the same line IFF its coordinate is between their coordinates.
Segment Addition Postulate
A property that states that segments of a line can be added together to form the whole line.
Congruent Segments
Segments that have the same length.
Segment Bisector
A segment, line, or plane that bisects a segment at the midpoint and divides the segment into two even parts.
Midpoint
The middle point of a line segment. Splits the segment into two equal halves.
Distance Between Two Points
How far apart two points are from each other.
Ray
Part of a line, has one fixed endpoint, and extends infinitely along the line from the endpoint.
Opposite Rays
Rays with a common endpoint, extending in opposite directions and forming a line.
Angle
The figure formed by two rays, called the sides of the angle, sharing a common endpoint, called the vertex of the angle.
Congruent Angles
Only have to have the same measure of angle.
Angle Addition Postulate
States that if point Z lies in the interior of ?ABC, then ?ABZ + ?CBZ = ?ABC.
Sides
The lines/rays/segments that form an angle.
Vertex
The point on an angle where the two lines/rays/segments meet.
Interior
The area between two sides of an angle where it is less than 180�.
Exterior
The area between two sides of an angle where it is great than 180�.
Right Angle
Any angle that measures 90�.
Acute Angle.
Any angle that measures <90�.
Obtuse Angle
Any angle that measures >90�.
Angle Bisector
A line or ray that evenly divides an angle in half.
Adjacent Angles
Two angles that have a common vertex and a common side.
Vertical Angles
Both of the pairs of opposite angles made by two intersecting lines. (X)
Linear Pair
Any pair of angles that share one side and add up to 180�
Complementary Angles
Any two angles whose measures have a sum of 90�.
Supplementary Angles
Any two angles whose measure have a sum of 180�.
Perpendicular Lines
Two lines that intersect to make a right angle.