Question

select a pair of vertical angles. * a and b b and c a and c

Explanation:

Step1: Recall vertical - angle definition

Vertical angles are formed when two lines intersect. They are opposite each other and have equal measures.

Step2: Identify vertical - angle pair

In the given figure, when two lines intersect, angle \(a\) and angle \(c\) are opposite each other, and angle \(b\) and angle \(d\) are opposite each other.

Answer:

a and c