Question

In figure, $AO=OB$ and $\angle A=\angle B$. State the matching pair you have used for $\Delta$ $AOC$ $\cong \Delta$ $BOD$, which is not given in the question.

Answer 1

It is given that

$AO=OB$ and

$\angle$ $A$ $=\angle$ $B$

Also, $\angle AOC=\angle BOD\cdots \left[\text{vertically opposite angles}\right]$

So, by $A.S.A.$ test,

$\Delta$ $AOC$ $\cong \Delta$ $BOD$

So, matching pair used which is not given in question is $\angle AOC=\angle BOD$ which are opposite angles