[tex]\bf \textit{Law of Cosines}\\ \quad \\
c^2 = {{ a}}^2+{{ b}}^2-(2{{ a}}{{ b}})cos(C)\implies
c = \sqrt{{{ a}}^2+{{ b}}^2-(2{{ a}}{{ b}})cos(C)}\\\\
-----------------------------\\\\
b = \sqrt{{{ a}}^2+{{ c}}^2-(2{{ a}}{{ c}})cos(B)}
\\\\\\
b=\sqrt{{{ 11}}^2+{{ 18}}^2-2(11\cdot 18)cos(104^o)}
\\\\\\
b\approx 23.25512998582180400481\implies b\approx 23.26[/tex]
so, "b" rounded up is 23.26, now, we know a = 11 and c = 18
well, to get the area then, let us use Heron's formula
[tex]\bf \textit{Heron's Area formula}\\\\
A=\sqrt{s(s-a)(s-b)(s-c)}\qquad
\begin{cases}
a=11\\
c=18\\
b\approx 23.26\\\\
s=\cfrac{a+b+c}{2}
\end{cases}[/tex]
