Given $\frac{b+c}{11}+\frac{c+a}{12}=\frac{a+b}{13}$ for $\Delta$ABC with usual

natation. If $\frac{\cos A}{\alpha }=\frac{\cos B}{\beta }=\frac{\cos C}{\gamma },$then the ordered triplet ($\alpha$, $\beta$, $\gamma$) has a value :