The correct option is
A 20
Given:
∠BOC=80° OA is a line which bisect the
∠BAC ![](https://search-static.byjusweb.com/question-images/byjus/infinitestudent-images/ckeditor_assets/pictures/504280/original_15.PNG)
We know that, an angle subtented by an arc at the centre is double the angle subtented by it at any point on the remaining part of the circle.
⇒∠BOC=2×∠BAC ∴∠BAC=40° OA is a line which bisect the
∠BAC Thus,
∠BAO=20° Consider
ΔAOB, OA=OB=r ∠OAB=∠OBA ..... (angles opposite equal sides are equal)
Hence,
∠ABO=20°