two angles that add up to 90 degrees
Two angles that add up to 180 degrees
Angles that have a common side and a common vertex (corner point).
A pair of opposite congruent angles formed by intersecting lines.
Angles that have the same measure
A pair of angles which are on the same side of the transversal, one must be interior, one must be exterior, and they must be nonadjacent
alternate interior angles
angles between 2 lines and on opposite sides of a transversal
alternate exterior angles
Angles that lay outside the parallel lines and are on opposite sides of the transversal; They are congruent.
A line that intersects two or more lines.
lines that never intersect