Radians and arc length

Radian measure arises from a simple idea: measuring an angle by the length of the arc it determines, relative to the radius.

Property — Radians and arc length

The measure in radians of an angle is the ratio between the corresponding arc and the radius. The length of an arc is obtained as: $\ell_{\text{arco}} = \alpha_{\text{rad}} \cdot r$

Links

Topics: Euclidean circle
Concepts: Arc · Radian
Skills: Using formulae