In the figure below, AB is the chord of a circle with center O. AB is extended to C such that BC = OB. The straight line CO is produced to meet the circle at D. If $$\angle{ACD}$$ = y degrees and $$\angle{AOD}$$ = x degrees such that x = ky, then the value of k is
Since Angle BOC = Angle BCO = y.
Angle OBC = 180-2y .
Hence Angle ABO = z = 2y = Angle OAB.
Now since x is exterior angle of triangle AOC .
We have x = z + y = 3y.
Hence option A.
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