a) \(2\widehat{A}=3\widehat{B}=6\widehat{C}\Rightarrow\frac{\widehat{A}}{3}=\frac{\widehat{B}}{2}=\frac{\widehat{C}}{1}=\frac{\widehat{A}+\widehat{B}+\widehat{C}}{3+2+1}=\frac{180}{6}=30\)
\(\Rightarrow\widehat{A}=90;\widehat{B}=60;\widehat{C}=30\)
b) Xin lỗi mình chưa nghĩ ra