A regular octagon is circumscribing a circle, the angle subtended by each side of the regular octagon at the center of the circle is :

1. 60°

2. 30°

3. 45°

4. (2 × 8 - 4) × 90°

ABC is a triangle. In order to draw a tangent PQ to the circle at point A, the angle BAQ is drawn equal to :

1. ∠BAC

2. ∠BCA

3. ∠ABC

4. ∠PAC

O is center of the the circle and ∠AOB = 60°. The length of chord AB is :

1. equal to radius of the circle

2. equal to the side of a regular pentagon

3. bigger than the radius of the circle

4. smaller than the radius of the circle.

The angle between two radii of a circle is 60°. The angle between their corresponding tangents is :

1. 60°

2. 90°

3. 120°

4. 150°