In cyclic quardrilateral ABCD, if ∠a=120°, then the circular of ∠C is

The circular value of each internal angle of a regular hexagon is

The measurement of Θ in the relations to S=rΘ is determined by

A. sexagesimal system

B. circular system

C. Those two methods

D. None of these

Let us write whether the following statements are true or false:

(i) The angle, formed by rotating a ray centering its end point in anticlockwise direction is positive.

(ii) The angle, formed for completely rotating a ray twice by centering its end point is 720°

Let us fill in the blanks:

(i) π radian is a ______angle.

(ii) In sexagesimal system 1 radian equals to ______(approx)

(iii) The circular value of the supplementary angle of the measure is_____