Answer
$a=3.02\;km$.
$c=21.84\;km$.
Work Step by Step
The given values are
$b=21.63\;km$
$B=82.06^{\circ}$.
By using trigonometric ratios in the figure Illustration 1.
$\frac{b}{c}=\sin{B}$
Isolate $c$.
$c=\frac{b}{\sin{B}}$
Plug all values.
$c=\frac{21.63\;km}{\sin{(82.06^{\circ})}}$
Simplify (Use degree calculator).
$c=21.84\;km$ (rounded value).
By using trigonometric ratios in the figure Illustration 1.
$\frac{b}{a}=\tan{B}$
Isolate $a$.
$a=\frac{b}{\tan{B}}$
Plug all values.
$a=\frac{21.63\;km}{\tan{(82.06^{\circ})}}$
Simplify (Use degree calculator).
$a=3.02\;km$ (rounded value).
