Question

Fill in the blanks :

In the figure :

_________ and $\angle COB$ are vertically opposite angles.

Answer 1

Vertically opposite angles :

When two lines intersect, the opposite angles are equal. These angles are called vertically opposite angles because they are opposite to each other at a vertex. As :

Now, as per the question :

$\angle AOD$ and $\angle COB$ are opposite to each other at vertex $O$.

Hence $\angle AOD$and $\angle COB$ are vertically opposite angles.