b)
[tex]\it\left.\begin{aligned}\it \hat A=\hat B \Rightarrow \hat C=\hat D\\ \\ \it \hat C+\hat D=260^o\end{aligned}\right\} \Rightarrow \hat C=\hat D=260^o:2=130^o\\ \\ \\ \hat A=\hat B=50^o\ (\ suplementul\ lui\ 130^o )[/tex]
