If ∠11≅∠16, then:
• Parallel Lines:, Lines m and n are not parallel.
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• Converse:, If lines m and n are not parallel, then it is possible that ∠11≅∠16.
If lines m and n were to be parallel, then ∠11 and ∠16 will be same-side interior angles and will therefore be supplementary. Since this does not hold, lines m and n are not parallel but just transversal lines intersecting x, y, and z.
