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complementary angles

two angles that add up to 90 degrees

supplementary angles

Two angles that add up to 180 degrees

adjacent angles

Angles that have a common side and a common vertex (corner point).

vertical angles

A pair of opposite congruent angles formed by intersecting lines.

congruent angles

Angles that have the same measure

corresponding angles

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.

transversal

A line that intersects two or more lines.

parallel lines

lines that never intersect