September 1999, Volume 92, Issue 6, Page 468
As Einstein stated, most fundamental concepts in science, including mathematics, are essentially simple. Students do not have to memorize and us radian measure without understanding the concept. The simple correspondence between the radial angle and the measure of its arc to the measuring of fractional parts of a wheel in terms of the number of spokes furnishes a concrete representation of the concept of radians.
Skill and Fluency