Basic Geometry Vocab

Geometry I (Dever 2023)

Point

location in space (points are dimesionless)

Line

at least 3 points to connect to create flat surface (continues forever in all directions) (2D)

Colinear

points on the same line

Coplanar

points together on the same plane

Line Segment

a position of a line that consists of 2 end points and all points between them

Ray

position of a line with one end point and extends forever in one direction

Angle

formed by 2 rays w. a common (same) endpoint

Sides (what are the 2 ray names?)

the 2 rays

\-initial ray/side

\-terminal ray/side

Vertex

common endpoint

Angle Measure

created by a rotation of the terminal ray around the vertex

Degrees

most common unit of angle measure

Positive Angle

counter clockwise rotation of terminal side

Negative Angle

clockwise rotation of terminal side

Acute Angle

Between 0-90 degrees

Right Angle

90 degrees

Obtuse Angle

between 90-180 degrees

Straight Angle

180 degrees

Complimentary Angles

Two angles that add up to 90 degrees.

Supplementary Angles

Two angles that add up to 180 degrees.

Standard Position

Initial ray is on the positive x-axis and if the terminal ray has a positive angle (counter clockwise motion)