Answer
$A=70^\circ$, $B=20^\circ$, and $a=609\ m$
Work Step by Step
Given $b=219\ m, c=647\ m$, we have $sinB=\frac{b}{c}=\frac{219}{647}$, thus $B=asin(\frac{219}{647})\approx 20^\circ$, $A=90^\circ- 20^\circ =70^\circ$, and $a=\sqrt {c^2-b^2}=\sqrt {647^2-219^2}\approx609\ m$
