a) sin$168^{\circ}$45'33'' $\approx$ 0,195 cos$17^{\circ}$22'35'' $\approx$ 0,954
tan$156^{\circ}$26'39'' $\approx$ -0,436 cot$56^{\circ}$36'42'' $\approx$ 0,659
b) i) sin$\alpha$ = 0,862 $\Rightarrow$ $\alpha$ = $22^{\circ}$43'6''
ii) cos$\alpha$ = - 0,567 $\Rightarrow$ $\alpha$ = $124^{\circ}$32'29''
iii) tan$\alpha$ = 0,334 $\Rightarrow$ $\alpha$ = $18^{\circ}$28'10''