Geometry Intro Vocabulary

Undefined Terms : The 3 most basic figures in geometry which cannot be defined using other figures: point, line, and plane

Point : Names a location and has no size. It is represented by a dot.

Ray : Part of a line that starts at an endpoint and extends forever in one direction.

Opposite rays : Two rays that have a common endpoint and form a line.

Midpoint : The point on a line segment that bisects, or divides, the segment into two congruent segments.

Angle : Figure formed by two rays, or sides, with a common endpoint.

Obtuse Angle : An angle that measures greater than 90 degrees and less than 180 degrees

Straight Angle : An angle formed by two opposite rays and measures 180 degrees

Adjacent Angles : Two angles in the same plane with a common vertex and a common side but no common interior points

Linear Pair Angles : A pair of adjacent angles whose noncommon sides are opposite rays forming a line