Geometry Vocab


a point has no demention. It is usually represents by a dot usues a capital block leter


A line has one demension it is usually represented by a straight line with two arrow reads that extends withous end


Has two demensions it is usually represented by a shapw that looks like a floor or a wall. You must imagine that it extens with out end, even though with edges

Collinear points

points that lie on the same line

Coplanar points

Points that lie on the same plane

Line Segment

part of a line consist of two points called end points


part of a line taht consists of a point on the line that extend in one dimention

Opposite rays

if point c lies on between A and B, then CA and CB are opposite rays


the set of points that figures have in common if two line intersect, always a single point, if two planes intersect, always a line


a rule that is accepted without proof


a true statement that follows a result of other true statements can be proven


the real number that corresponds to a point of a line


the absolute value of the difference of the coordinates of the points the DIstance between points A and B written as AB, is also called the length of AB


When three points lie on a line, you can say that one point is between the other two

Congruent segments

line segments taht have the same length

Segment Addistion Postulate

Can be used whoever there are three colinear points.


a point that divides, or bisects, a segment into two congruent segments

Segment Bisector

A point, ray, line, segment, or plane that intersects a segment at its midpoint


consists of two different rays with the same end points

sides of an angle

the rays that form the angle

vertex of an angle

the common end point

measure of an angle

the muesutre of an angle is a measure of the separation of the two sides of the angle. THe unites for the measure of an angle are degres

Acute angle

An angle with a measure between 0 and 90

Right angle

angle with a measure equal to 90

Obtuse angles

an angle with the measure between 90 and 180

Straight angle

an angle with a measure of 180

Congruent angles

angles that have the same measure

Angle bisector

a ray flat divides an angles that are congruent

Adjacent angles

two angles taht share a common vertex and side, but share no common interior points

Complementary angles

two angles whose measures have the sum of 90 the sum of the measure of an angle and its complement is 90 Do not have to be adjacent

Supplementary angles

two angles whose measures have the sum of 180 the sum of the measures of an angle and its supplement is 180

linear pair

two adjecent angles whose non common sides are the opposite rays, a linear pair is always 3/4 supplementary, but supplementary adjaycent and angles are not always a linear pair

vertical angels

two angles whose sides form two pairs of opposite rays vertical angles are formed by intercecting lines


a closed figure with these properties, it is formed by three or more lines segments called sides each side intersects exactly two sides one and each end point, so that no two sides with a comon end point are collinear


each line semgent had forms of polygons


each end point of a side of a polygon plural is verticles


a olygon that is not convex


a polygon with n sides


a polygon with all its sides are congruent


a polygon with all of it's interial angles congruent


a polygon taht has all sides and all angles congruent