## Trigonometry (11th Edition) Clone

$r=\frac{L}{\theta}$
Since the figure containing $L$, $r$ and $\theta$ represents a sector of a circle, $L$ is therefore equal to the arc length. The general formula for arc length $s$ of a sector of a circle is $s=r\theta$. Since $L$ is equal to $s$, this formula can be written as $L=r\theta$. Solving for $r$, the formula becomes $r=\frac{L}{\theta}$.