yup OA is D ...man you are damm good...
can you please explain why the angle BCO = 2 OAB
i.e why x=2x
in this equation
x + (2x+60) +60 = 180
Because BO = OC = radius
=> Trainge CBO is an isoceles triangle
=>Angle BOC = COB
Now CBO is sum of 2 angles each of which is x. Reason for this is:
There are 2 parallel lines.
1. The diameter
2. The line drawn from B which is parallel to the diameter (say BE)
These two are cut by OB. Angles on the either side of a line (transversal) that cuts two paralle lines are equal. So EBO = BOC
Now CBE = CAO again because diameter is paralle to BE
Good luck for your test!! I am sure you will do well.
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