In the given figure, O is the centre of the circle in which ∠OBA = 30° and ∠OCA = 40°. Then, ∠BOC = ?

1. 70°

2. 100°

3. 120°

4. 140°

In the given figure, O is the centre of the circle.
If ∠AOB = 110° and ∠AOC = 80°, then ∠BAC = ?

1. 75°

2. 80°

3. 85°

4. 95°

In the given figure, O is the centre of the circle and ∠AOB = 150°. Then, ∠ACB = ?

1. 75°

2. 105°

3. 85°

4. 115°

In the given figure, ABCD is a cyclic quadrilateral. The measure of its greatest angle is :

1. 135°

2. 140°

3. 150°

4. 160°