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In figure, BC is a diameter of the circle and ∠BAO = 60º. Then ∠ADC is equal to ______.

#### Options

30º

45º

60º

120º

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#### Solution

In figure, BC is a diameter of the circle and ∠BAO = 60º. Then ∠ADC is equal to **60º**.

**Explanation:**

**Given:** BC is a diameter of the circle and ∠BAO = 60º

Now, in triangle OAB,

OA = OB .....[Radii of the same circle]

So, ∠ABO = ∠BAO ......[Angle opposite to equal sides are equal]

∠ABO = ∠BAO = 60º ......[Given]

Now, ∠ADC = ∠ABC = 60º .....[∠ADC and ∠ABC are angles in the same segment of a circle are equal]

Therefore, ∠ADC = 60º.

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