Unit One Vocabulary


A point is a location with no size or shape


A line is made up of points with no thickness or width


A plane is a flat surface made up of points that extends indefinitely in all directions


Points that lie on the same line, non col-linear points that don't lie on the same line

Co planar

Points that lie on the same plane. Non co planar points don't lay on the same line

Line Segment

A measurable part of the line consisting of two endpoints

Distance Formula

A formula used to find the distance between two points on a coordinate plane

Congruent Segments

If two segments have the same length then the are congruent

Midpoint Formula

A formula used to find the midpoint between two endpoints

segment bisector

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


A line that extends indefinitely in one direction


the intersection of two rays at an endpoint


The common endpoint of an angle (where the sides intersect)

Right Angle

an angle that measures 90 degrees

Acute Angle

an angle that measures less than 90 degrees

Obtuse Angle

an angle greater than 90 degrees

congrent angles

angles that have the same measure are congruent

Adjacent Angles

Two angles that share a common side and vertex. Next to each other

vertical Angles

Two angles with measures that have a sum of 90 degrees but do not have to be adjacent

Complimentary angles

two angles that add up to 90 degrees

supplementary angles

Two angles whose sum is 180 degrees

Linear Pair

Adjacent angles that are supplementary. Combined, they form a straight line.


Two lines that intersect at a 90 degree right angle

Angle Bisector

A line or ray that divides an angle into two equal parts