An isosceles trapezium is always :

1. a parallelogram

2. a square

3. a rectangle

4. a cyclic quadrilateral

Which of the following quadrilaterals is not always a cyclic quadrilateral?

1. square

2. rhombus

3. rectangle

4. an isosceles trapezium

In the given figure, O is the centre of the circle and ∠ACB = 30°. Then, ∠AOB = ?

1. 15°

2. 30°

3. 60°

4. 90°

In the given figure, O is the centre of the circle. If ∠OAB = 35° and C is a point on the circle, then ∠ACB = ?

1. 35°

2. 55°

3. 45°

4. 75°