How Many Radians Are in a Circle?
The number of radians in a circle is equal to 2 pi, or approximately 6.28. Since there are 360 degrees in a circle, each radian is equal to 360 divided by 6.28, approximately 57.3 degrees.
A radian is the measure of the central angle of a circle that forms an arc equal in length to the radius of the circle. In other words, if the length of the radius is wrapped around the edge of a circle, the central angle that generates that arc measures one radian. In calculus and most other forms of higher mathematics, angles are nearly always measured in radians rather than degrees.