Convert between Degrees and Radians (solutions, examples, videos, worksheets, activities)
What is Radian? - Definition - Teachoo - Radian measure - Conversion
Radians
Degree (angle) - Wikipedia
Radian -- from Wolfram MathWorld
Illustrative Mathematics
Radians In a circle of radius 1 unit, the angle subtended at the centre of the circle by the arc of length 1 unit is called 1 radian, written as 1 rad. - ppt download