Question

prove that if lines interest each others their the vertically opposite angles are equal​

Answer 1

Answer:

⇒∠AOC=180∘−180∘+∠BOD. ⇒∠AOC=∠BOD. From the figure, we can see that the angles ∠AOC and ∠BOD are vertically opposite angles. So, we have proved that if two lines intersect each other, then the vertically opposite angles are equal.

Answer 2

Answer:

Let us consider the angles on the line CD. So, we get ∠COB+∠BOD=180∘. ⇒∠COB=180∘−∠BOD ---(1). ... So, we have proved that if two lines intersect each other, then the vertically opposite angles are equal.