# Unwrapping a Circle

- Author:
- tcoe

This is a tool to help students envision the meaning of "radian" by thinking in terms of radius-lengths.
To use:
1. Adjust length.
2. Adjust radius.
3. Guess the radian measure of the arc by envisioning how many radius-lengths the arc is in length.
4. Select "Show Radius Scale."
5. Move the "unwrap" slider to the right.
By Ted Coe, tedcoe.com, 2011.