We know that π rad = 180° ⇒ 1 rad = 180°/ π
(i) Given \(\frac{9π}5\)
= \((\frac{180}π\times\frac{9π}5)^°\)
= (36 × 9) °
= 324°
(ii) Given \(-\frac{5π}6\)
= \((\frac{180}π\times-\frac{5π}6)^°\)
= (30 × - 5) °
= - (150) °
(iii) Given \((\frac{18π}5)^c\)
= \((\frac{180}π\times\frac{18π}5)^°\)
= (36 × 18) °
= 648°
(iv) Given (-3)c
= \((\frac{180}π\times-3)^°\)
= \((\frac{180}{22}\times7\times-3)^°\)
= \((-\frac{3780}{22})^°\)
= \((-171\frac{18}{22})°\)
= \((-171°(\frac{18}{22}\times{60})')\)
= \((-171°(49\frac{1}{11})')\)
= \((-171°{49}'(\frac{1}{11}\times60)')\)
= -(171° 49’ 5.45”)
≈ -(171° 49’ 5”)
(v) Given 11c
= \((\frac{180}π\times11)^°\)
= \((\frac{180}{22}\times7\times11)^°\)
= (90 × 7) °
= 630°
(vi) Given 1c
= \((\frac{180}π\times1)^°\)
= \((\frac{180}{22}\times7\times1)^°\)
= \((\frac{1260}{22})^°\)
= \(({57}\frac{3}{11})^°\)
= \(({57}°(\frac{3}{11}\times{60})')\)
= \(({57}°({16}\frac{4}{11})')\)
= \((57°16'(\frac{4}{11}\times60)')\)
= (57° 16’ 21.81”)
≈ (57° 16’ 22”)