Which postulate should be used to find the value A?
 


a. Alternate Interior Angles Theorem
b. Vertical angles congruence Theorem
c. Alternate Exterior Angles Theorem
d. Corresponding Angles Postulate

The correct answer is: ⇒∠A=60°

SOLUTION:
HINT: Use the property of parallel lines angle rules.
Complete step by step solution:
Here we can use vertical angles congruence theorem.
That is, we have vertically opposite angles to be equal.