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Lines

made up of a series of points that extend in two opposite directions

point

exact location in space

segment

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

ray

A part of a line, with one endpoint, that continues without end in one direction

collinear

points that lie on the same line

plane

A flat surface that goes on forever in all directions

intersecting lines

lines that have exactly one point in common

Parallel lines

Lines that have no points in common

skew lines

lines that are not parallel and do not intersect

angle

two rays with a common endpoint, called the vertex

vertex

The common endpoint of an angle

acute angle

less than 90 degrees

right angle

an angle that measures 90 degrees

obtuse angle

measures between 90 and 180 degrees

straight angle

an angle whose measure is 180 degrees

perpendicular lines

Two lines that intersect to form right angles

degrees

a unit for measuring angles