Answer
$A= 24^\circ10'$, $B= 65^\circ50'$, and $b= 42.3\ cm$
Work Step by Step
Given $a=18.9\ cm, c=46.3\ cm$, we have $sinA=\frac{a}{c}=\frac{18.9}{46.3}$, thus $A=asin(\frac{18.9}{46.3})\approx 24^\circ10'$, $B=90^\circ- 24^\circ10'=65^\circ50'$, and $b=\sqrt {c^2-a^2}=\sqrt {46.3^2-18.9^2}\approx42.3\ cm$
