Lawrence Hall of Science
The Math Page: Trigonometry: Radian Measure
Here is a site that clearly and thoroughly explains the radian measure of angles. There are example problems solved, problems for the student to attempt, and answers to the student problems.
Savvas Learning
Pearson Education: Radian and Degree Angle Measures [Pdf]
This resource details how to convert between radians and degrees with worked examples. It also looks at special radian measures that are used often.
Illustrative Mathematics
Illustrative Mathematics: F Tf.1 What Exactly Is a Radian?
For this task, students use a piece of string or another tool to measure the radius of the circle and then mark off the corresponding arc length on the unit circle as many times as they need to for 0, 1, 2, 3, 4, 5, and 6 radians. They...
Illustrative Mathematics
Illustrative Mathematics: F Tf Bicycle Wheel
The purpose of this task is to introduce radian measure for angles in a situation where it arises naturally, in this case the movement of a bicycle wheel. Aligns with HSF-TF.A.1.