Investigate Area of a Sector and Arc Length

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)