AMOSi:Radians And Angles
In trigonometry, a radian is the angle subtended by an arc whose length is equal to the radius of a circle. This angle is formed by two radii of a circle that cut off an arc on the circumference that is equal in length to the radius. One radian is equal to 57.296 degrees. The Amiga prefers to use radians instead of degrees, but you can change that with the DEGREE command.