How to find an angle in a polygon Practice Test

$\tan\left( \frac{s}{r} \right)$

$\tan\left( \frac{r}{s} \right)$

$\tan^{-1}\left( \frac{r}{s} \right)$

$\sin^{-1}\left( \frac{r}{s} \right)$

$\tan^{-1}\left( \frac{s}{r} \right)$