Question

In the given figure, lines $AB$ and $CD$ intersect at point $O$.​(ii) Name all the pairs of vertically opposite angles.

Answer 1

Given, Line $AB$ and $CD$ intersect at point $O$ .

Now we know that , when two straight lines intersect the angles on the opposite sides of their point of interection called vertically opposite angles.
From figure we have,
Vertically opposite angle are:

$\angle AOC$ and $\angle BOD$

$\angle AOD$ and $\angle BOC$

Hence, above given angles are the vertically opposite angles.