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


exact location in space


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


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


points that lie on the same line


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


two rays with a common endpoint, called the 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


a unit for measuring angles

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