Giải thích các bước giải:
\(\begin{array}{l}
\widehat A = 180^\circ - \widehat B - \widehat C = 75^\circ \\
\frac{a}{{\sin A}} = \frac{b}{{\sin B}} = \frac{c}{{\sin C}} = 2R\\
\Leftrightarrow \frac{a}{{\sin 75^\circ }} = \frac{{3 + \sqrt 3 }}{{\sin 45^\circ }} = \frac{c}{{\sin 60^\circ }} = 2R\\
\Leftrightarrow \left\{ \begin{array}{l}
R = \frac{{\sqrt 6 + 3\sqrt 2 }}{2}\\
a = 3 + 2\sqrt 3 \\
c = \frac{{3\sqrt 6 + 3\sqrt 2 }}{2}
\end{array} \right.\\
{S_{ABC}} = \frac{{abc}}{{4R}} = \frac{{27 + 15\sqrt 3 }}{4}\\
{h_a} = \frac{{2{S_{ABC}}}}{a} = \frac{{3 + 3\sqrt 3 }}{2}
\end{array}\)
