Alternate interior/exterior angles are congruent where a transversal crosses parallel lines. The angles are congruent if and only if the lines are parallel.
Same-side interior/exterior angles are supplementary where a transversal crosses parallel lines. The angles are supplementary if and only if the lines are parallel.
Linear angles are supplementary, a fact that can be combined with either of the above to derive more angle relationships.
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In the attached, the statements that are untrue are lined through in red.
Alternate interior/exterior angles are congruent where a transversal crosses parallel lines. The angles are congruent if and only if the lines are parallel.
Same-side interior/exterior angles are supplementary where a transversal crosses parallel lines. The angles are supplementary if and only if the lines are parallel.
Linear angles are supplementary, a fact that can be combined with either of the above to derive more angle relationships.
