Question

In the figure 0 is the centre of the circle and ABC= 140° find y.

Answer 1

I can't see the figure/image/attachment..

therefore unable to understand the question

Answer 2

Answer:

Given that ∠AOC=140∘

∠ABC=2140=70∘

Because WKT angle made by a chord aa any point on the circle is half the angle made by it at the center

In △AOC

AO=CO=radius

⟹∠OAC=∠OCA

And

2∠OCA=180−∠AOC

⟹∠OCA=240=20=∠OAC

 In △ABC

AB=BC

⟹∠BAC=∠BCA

And

2∠BAC=180−∠ABC

⟹∠BAC=55

∠OAB=∠CAB−∠CAO=55–20=