Answer:
see explanation
Step-by-step explanation:
When 2 lines intersect to make an X, angles on opposite sides of the X are called vertical angles , and they are congruent (equal )
From the given diagram there are 4 pairs of vertical angles.
∠ 1 & ∠ 3 , ∠ 2 & ∠ 4 , ∠ 5 & ∠ 7 , ∠ 6 & ∠ 8