Question

. in the given figure, if O is the center of the circle, angleAOC=50deg and angleB=15deg. Find angle AOB.

Answer 1

Answer:

∠ADC=

2

1

∠AOC

(Angle subtended by a chord on mayor area is half of that subtended on center)

∴∠ADC=

2

1

×130=65

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Now, ADCB is cyclic quadrilateral ⇒

Sum of opposite Angles is 180

∘

∴∠ABC+∠ADC=180

∘

∠ABC+65=180

∘

∠ABC=115

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