The measure of ∠8 is 120°
Solution:
Given line AB parallel to line CD.
m∠2 = 60°
∠2 and ∠6 are corresponding lines.
If two lines are parallel, then their corresponding lines are congruent.
m∠2 = m∠6
m∠6 = 60°
Sum of the adjacent angles in a straight line is 180°.
m∠6 + m∠8 = 180°
60° + m∠8 = 180°
Subtract 60° from both sides.
60° + m∠8 - 60° = 180° - 60°
m∠8 = 120°
The measure of ∠8 is 120°.