Answer
$a =0.6943km$
$B =114.2^\circ$
$C= 22.467^\circ$
Work Step by Step
$20' = \dfrac{20}{60}^\circ=\dfrac{1}{3}^\circ$
$a^2 = b^2+c^2-2ac \cos{A^\circ} \\= (0.923)^2+(0.387)^2-2 \times 0.923 \times 0.387 \cos{43.333^\circ}= 0.482$
$$a = \boxed{0.6943 \hspace{1pt} km}$$
$\cos{B} = \dfrac{a^2+c^2-b^2}{2ac} = \dfrac{(0.6943)^2+(0.387)^2-(0.923)^2}{2 \times 0.6943 \times 0.387} = -0.41$
$$\therefore B =\boxed{114.2^\circ} $$
$$C = 180-(A+B) = 180-(43.333+114.2) = \boxed{22.467^\circ}$$
