Ta có: \(\widehat{A} = 180^0- (\widehat{B}+ \widehat{C}) = 40^0\)
Áp dụng định lí \(\sin\) : \(\frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C}\), ta có:
\(b =\frac{a \sin B}{\sin A}= \frac{137,5.\sin83^{0}}{\sin40^0} ≈ 212,31cm.\)
\(c =\frac{a \sin C}{\sin A}= \frac{137,5.\sin57^{0}}{\sin40^0} ≈ 179,40cm.\)
