## Trigonometry 7th Edition

$198^{\circ}$
Given- $\sin\theta$ = - $0.3090$ , $\theta$ belongs to Q III We will find reference angle of $\theta$ first, using calculator in degree mode by the $\sin^{-1}$ key with the positive value $0.3090$- $0.3090$ → $\sin^{-1}$→→ 17.998976188 i.e. reference angle of $\theta$ = $18^{\circ}$ (to the nearest degree) The desired angle $\theta$ is in Q III, whose reference angle is $18^{\circ}$. Therefore- $\theta$ = $180^{\circ} + 18^{\circ}$ = $198^{\circ}$