ABCD is a cyclic quadrilateral and O is the centre of the

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ABCD is a cyclic quadrilateral and O is the centre of the circle. If ∠COD = 140° and ∠BAC = 40°, then the value of ∠BCD is equal to

1. 70°
2. 90°
3. 60°
4. 80°

Correct Option: A

As per the given in question , we draw a figure cyclic quadrilateral ABCD ,

The angle subtended at the centre by an arc is twice to that of angle subtended at the circumference.

∴ ∠CAD =	1	∠COD = 70°
	2

∴ ∠BAD = 70° + 40° = 110°
∴ ∠BCD = 180° – 110° = 70°