High School Geometry

Construction

A construction is a way of creating a figure that is more precise.

Angle

A figure formed by two rays, or sides, with a common endpoint called the vertex.

Line

A line is a straight path that has not thickness and extends forever.

Ray

A part of a line that starts at an endpoint and extends forever in one direction

Plane

A plane is a flat surface that has no thickness and extends forever.

Endpoint

A point at one end of a segment or the starting point of a ray.

Coordinate

A point corresponds to one and only one number on a ruler. The number is called a coordinate.

Point

A point is a location and has no size. It is represented by a dot.

Angle Bisector

A ray that divides an angle into two congruent angles

Postulate or axiom

A statement that is accepted as true without proof. (Postulates about points, lines , and planes help describe geometric properties)

Adjacent Angles

Are two angles in the same plane with a common vertex and a common side, but no common interior points. (1 and 2 are adjacent angles)

Complementary angles

Are two angles whose measures have a sum of 90 degrees ((90-x) degrees)

Vertical angles

Are two nonadjacent angles formed by two intersecting line.

Undefined terms

Cannot be defined by using other figures. (The undefined terms point, line , and plane are the building blocks of geometry )

Linear pair

Of angles is a pair of adjacent angles whose non common sides are opposite rays.

Collinear

Points that lie on the same line are collinear.

Coplanar

Points that lie on the same plane are coplanar

Length

The distance between A and B is also called the length of AB, or AB

Distance

The distance between any two points is the absolute value of the difference of the coordinates.

Segment or line segment

The part of a line consisting of the two points and all points between them.

Interior of an angle

The set of all points between the sides of the angle is the...

Exterior of an angle

The set of all points out side of the angle.

Supplementary Angles

Two angles whose measures have a sum of 180 degrees( (180-x)degrees )

Opposite rays

Two rays that have a common endpoint and form a line.