Rotate point C counterclockwise to change angle A, and move point B to change the radius.
1) What is the relationship between the circumference of the circle and 1 revolution? What is the relationship between the arc length s and the angle theta? Derive equation (1).
2) What is the relationship between the area of the circle and 1 revolution? What is the relationship between the area of the sector and the angle theta? Derive equation (2)