Download Chapter 1 Vocabulary Definitions

Chapter 1 Vocabulary Definitions
Undefined terms- point, line, plane; 3 in Geometry
Collinear points- points that lie in the same line
Coplanar points- points that lie in the same plane
Line- extends without end in two directions; one dimensional
Segment- part of a line that consists of two endpoints and all points between the endpoints
Ray- part of a line that consists of a point (initial point) and all points on the line that extend in
one direction
Endpoints- the beginning and ending points of a segment or the beginning point of a ray.
Opposite rays- two rays that have the same initial point and its between a point on each ray
Intersection- two or more geometric figures intersect if they have one or more points in
common
Postulates or axioms- rules that are accepted without proof
Coordinates- the real number that corresponds to a point
Distance- the absolute value of the difference between the coordinates of two points
Length- AB with no bar
Between- when (3) points lie on a line you can say (1) of them is between the other two
Angle- two different rays that have the same endpoint
Sides- the rays that form an angle.
Vertex- the common endpoint of two rays that form an angle.
Congruent angles- angles that have the same measure
Acute angle- an angle greater than 0 degrees but less than 90 degrees
Right angle- a 90 degree angle
Obtuse angle- an angle that is greater than 90 degrees but less than 180 degrees
Straight angle- a 180 degree angle
Adjacent angles- share a common vertex, common side and have no common interior points
Midpoint- the point that divides a segment into two congruent parts
Segment bisector- can be a ray, line or plane
Angle bisector- a ray that divides an angle into 2 adjacent angles that are congruent
Vertical angles- two angles whose sides form two pairs of opposite rays
Linear pair- two adjacent angles whose non-common sides are opposite rays
Complementary angles- two angles whose sum is 90 degrees
Supplementary angles- two angles whose sum is 180 degrees
Polygon – a closed figure that is formed by three or more segments (sides) that intersect only at
there endpoints.
Convex – a polygon in which no line containing a side of the polygon contains a point in the
interior of the polygon.
Concave – not convex
n-gon – a polygon with n sides.
Equilateral – a polygon with all sides congruent.
Equiangular – a polygon with all angles congruent.
Regular – a polygon that is equilateral and equiangular.