Đáp án:
$\begin{array}{l}
1)a = 35;b = 20;\widehat C = {62^0}\\
Do:{c^2} = {a^2} + {b^2} - 2.a.b.cos\widehat C\\
= {35^2} + {20^2} - 2.35.20.cos{62^0}\\
= 967,74\\
\Rightarrow c = 31,1\left( {cm} \right)\\
\dfrac{c}{{\sin \widehat C}} = \dfrac{b}{{\sin B}}\\
\Rightarrow \sin \widehat B = 20:\dfrac{{31,1}}{{\sin {{62}^0}}} = 0,567\\
\Rightarrow \widehat B = {34^0}\\
B2)\\
a = 15;\widehat B = {79^0};\widehat C = {32^0}55'\\
\widehat A = {180^0} - \widehat B - \widehat C = {68^0}5'\\
\dfrac{a}{{\sin \widehat A}} = \dfrac{b}{{\sin \widehat B}} = \dfrac{c}{{\sin \widehat C}}\\
\Rightarrow \left\{ \begin{array}{l}
b = 15,87\\
c = 8,78
\end{array} \right.
\end{array}$
