Theo đề bài, ta có:
\(\widehat{A}+\widehat{B}+\widehat{C}=180^o\)
\(\frac{\widehat{A}}{13}=\frac{\widehat{B}}{12}=\frac{\widehat{C}}{16}\)
Áp dụng tính chất dãy tỉ số bằng nhau, ta có:
\(\frac{\widehat{A}}{13}=\frac{\widehat{B}}{12}=\frac{\widehat{C}}{16}=\frac{\widehat{A}+\widehat{B}+\widehat{C}}{13+12+16}=\frac{180}{41}\)
Suy ra:\(\hept{\begin{cases}\widehat{A}=\frac{180}{41}\cdot13=\left(\frac{2340}{41}\right)^o\\\widehat{B}=\frac{180}{41}\cdot12=\left(\frac{2160}{41}\right)^o\\\widehat{C}=\frac{180}{41}\cdot16=\left(\frac{2880}{4}\right)o^{ }\end{cases}}\)
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