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$\displaystyle \sin A = \frac{3}{5} , \cos A = \pm \frac{4}{5}$ $\displaystyle \sin B = \frac{3}{5}$, $\displaystyle \cos B = \frac{4}{5}$ $\sin C = \sin \left\{ \pi - ( A + B ) \right\} = \sin ( A + B )$ $\displaystyle = \sin A \cos B + \cos A \sin B = \frac{12}{25} \pm \frac{12}{25}$ $\sin C > 0$이므로 $\displaystyle \sin C = \frac{24}{25}$ 따라서 $\displaystyle \sin A : \sin B : \sin C = \frac{3}{5} : \frac{3}{5} : \frac{24}{25} = 5 : 5 : 8$