Two parallel lines are cut by a transversal. What is the measure of <1?
A 80
В. 180
C. 100
D. 90

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Answer:
C. 100°
Step-by-step explanation:
Consecutive (same-side) exterior angles are supplementary.
∠1 = 180° -∠7 = 180° -80°
∠1 = 100°