Radians are a way of measuring angles that come directly from the geometry of a circle. Instead of using degrees, which divide a circle into 360 equal parts, radians measure angles by comparing the length of an arc to the circle’s radius. One radian is the angle made when the arc length is exactly equal to the radius. Since the circumference of a circle is about 6.28 times the radius, a full circle contains about 6.28 radians, which is more precisely written as 2π radians. This makes radians a n