Question

Convert $-47°30\text{'}$ into radian measure.

Answer 1

$$\begin{gathered} 180°=\mathrm{\pi }\mathrm{radian} \\ 1°=\frac{\mathrm{\pi }}{180}\mathrm{radian} \\ -47°30\text{'}=-{\left(47\frac{1}{2}\right)}^{°} \\ =-{\left(\frac{95}{2}\right)}^{°} \\ =-{\left(\frac{95}{2}\right)}^{°}\times \frac{\mathrm{\pi }}{180}\mathrm{radian} \\ =-\frac{19\mathrm{\pi }}{72}\mathrm{radian} \end{gathered}$$

Therefore $-47°30\text{'}=-\frac{19\mathrm{\pi }}{72}radian$