Answer
$A=47.7^{\circ}$.
$a=700.05\;m$.
$c=946.5\;m$.
Work Step by Step
The given values are
$B=42.3^{\circ}$
$b=637\;m$.
In a right angle triangle sum of other two angles is $90^{\circ}$.
$A+B=90^{\circ}$
Isolate $A$.
$A=90^{\circ}-B$
Plug value of $B$.
$A=90^{\circ}-42.3^{\circ}$
Simplify.
$A=47.7^{\circ}$.
By using trigonometric ratios.
$\frac{b}{c}=\sin{B}$
Isolate $c$.
$c=\frac{b}{\sin{B}}$
Plug all values.
$c=\frac{637\;m}{\sin{(42.3^{\circ})}}$
By using degree calculator simplify.
$c=946.5\;m$ (rounded value).
By using trigonometric ratios.
$\frac{b}{a}=\tan{B}$
Isolate $a$.
$a=\frac{b}{\tan{B}}$
Plug all values.
$a=\frac{637\;m}{\tan{(42.3^{\circ})}}$
By using degree calculator simplify.
$a=700.05\;m$ (rounded value).