- The radian is a pure measured based on the radius of the circle. It is the angle made by taking the radius and wrapping it along the edge of a circle. www.youtube.com/watch?v=7QhgYX8cRE
- Radians and the unit circle are related because the unit circle is used in trigonometry to define cosine and sine of an angle.
- C = 2 pi r = 2 pi 1 = 2 pi 2 pi = 360 degrees
- Radians and degrees are two units for measuring angles. I prefer degrees becuse I'm used to them and so it's easier for me, but radians are more mathematically "pure".