25 terms

Point

Indicates a location and has no size.

Line

Represented by a straight path that extends in two opposite directions without end.

Plane

Represented by a flat surface that extends without end and has no thickness.

Collinear Points

Points that lie on the same line.

Coplanar

Points and lines that lie in the same plane.

Segment

Part of a line that has two endpoints and all points between them.

Ray

Part of a line that has one endpoint.

Opposite Rays

Two rays that share the same endpoint and form a line.

Postulate

Accepted statement of fact.

Midpoint

A point that divides the segment into two congruent segments.

Congruent Segments

Segments with the same measure.

Angle

Formed by two rays with the same endpoint.

Vertex of an Angle

The endpoint of the angle where the rays meet.

Acute Angle

An angle who has a measure: 0 < x < 90°.

Right Angle

An angle that has the measure of 90°.

Obtuse Angle

An angle who has a measure: 90° < x < 180°.

Straight Angle

An angle with a measure of 180°.

Congruent Angles

Angles with the same measure.

Adjacent Angles

Coplanar angles with a common side, common vertex, and no common interior points (next to each other).

Vertical Angles

Two angles whose sides are opposite rays (across from each other).

Complementary Angles

Two angles whose measures have a sum of 90°.

Supplementary Angles

Two angles whose measures have a sum of 180°.

Linear Pair

Two adjacent angles with noncommon sides as opposite rays and are supplementary.

Angle Bisector

Ray that divides an angle into two congruent angles.

Protractor

An instrument that measures angles.