Find the radian measure corresponding to the following degree measures:
(i) 300°
(ii) 35°
(iii) −56°
(iv) 135°
(v) −300°
(vi) 7° 30'
(vii) 125° 30'
(viii) −47° 30'
We have :
$180^{\circ}=\pi \mathrm{rad}$
$\therefore 1^{\circ}=\frac{\pi}{180} \mathrm{rad}$
(i) $300^{\circ}$
$=\left(300 \times \frac{\pi}{180}\right)$
$=\frac{5 \pi}{3} \mathrm{rad}$
(ii) $35^{\circ}$
$=35 \times \frac{\pi}{180}$
$=\frac{7 \pi}{36} \mathrm{rad}$
(iii) $-56^{\circ}$
$=-\left(56 \times \frac{\pi}{180}\right)$
$=-\frac{14 \pi}{45} \mathrm{rad}$
(iv) $135^{\circ}$
$=135 \times \frac{\pi}{180}$
$=\frac{3 \pi}{4} \mathrm{rad}$
$(\mathrm{v})-300^{\circ}$
$=-\left(300 \times \frac{\pi}{180}\right)$
$=-\frac{5 \pi}{3} \mathrm{rad}$
(vi) $30^{\prime}=\left(\frac{1}{2}\right)^{\circ}$
$\therefore 7^{\circ} 30^{\prime}=\left(7 \frac{1}{2}\right)^{\circ}$
$=\left(\frac{15}{2}\right)^{\circ}$
$=\frac{15}{2} \times \frac{\pi}{180}$
$=\frac{\pi}{24} \mathrm{rad}$
(vii) $30^{\prime}=\left(\frac{1}{2}\right)^{\circ}$
$\therefore 125^{\circ} 30^{\prime}=\left(125 \frac{1}{2}\right)^{\circ}$
$=\left(\frac{251}{2}\right)^{\circ}$
$=\frac{251}{2} \times \frac{\pi}{180}$
$=\frac{251 \pi}{360} \mathrm{rad}$
(viii) $30^{\prime}=\left(\frac{1}{2}\right)^{\circ}$
$\therefore 47^{\circ} 30^{\prime}=-\left(47 \frac{1}{2}\right)^{\circ}$
$=-\left(\frac{95}{2}\right)^{\circ}$
$=-\left(\frac{95}{2} \times \frac{\pi}{180}\right)$
$=-\frac{19 \pi}{72}$ rad