A three or more coplanar lines that intersect at exactly one point.
Concurrent Lines
Two coplanar lines that have a point in common.
Intersecting Lines
Non-coplanar lines that do not intersect and are not parallel.
Skew Lines
Two angles are called __________ if their sum is 180⁰.
Supplementary Angles
Two angles with a common vertex, a common side, but no common interior points.
Adjacent Angles
Coplanar lines that do not intersect.
Parallel Lines
Formed when two straight lines intersect each other. Their sides form two pairs of opposite rays and their angles are non-adjacent.
Vertical Angles
Two angles are called __________ if their sum is 90⁰.
Complementary Angles