In the given figure, O is centre of the circle.
If ∠AOC = 130°, then the value of x is :

1. 25°

2. 50°

3. 65°

4. 40°

In the given figure, O is the centre of the circle, ∠AOB = 40° and ∠BDC = 100°. The measure of ∠OBC is :

1. 40°

2. 80°

3. 60°

4. 20°

Assertion (A): In the given figure, if O is the centre of the circle, then ∠ACB = 40°.

Reason (R): Angle at the centre is double the angle at the remaining part of the circle.

1. A is true, R is false

2. A is false, R is true

3. Both A and R are true

4. Both A and R are false

Assertion (A): In the figure, ∠ACB = 70°.

Reason (R): Opposite angles of a cyclic quadrilateral are equal.

1. A is true, R is false

2. A is false, R is true

3. Both A and R are true

4. Both A and R are false