Answer
$49.0^\circ$
Work Step by Step
Given $a=17.3\ ft, b=22.6\ ft, c=29.8\ ft$, use the Law of Cosines, we have
$b^2=a^2+c^2-2ac\ cosB$ that is $22.6^2=17.3^2+29.8^2-2(17.3)(29.8)\ cosB$, thus $cosB=\frac{17.3^2+29.8^2-22.6^2}{2(17.3)(29.8)}\approx0.6562$ and $B=acos(0.6562)\approx49.0^\circ$
