Question

  Giúp e Câu 6 với ạ, em cần gấp, e cảm ơn trước ạ

Answer 1

\(cos\widehat{BAC}=\dfrac{b^2+c^2-a^2}{2bc}=\dfrac{100^2+92^2-58^2}{2.100.92}=\dfrac{15100}{18400}\approx0,82\)

\(\Rightarrow\widehat{BAC}\approx35^o\)

\(S_{ABC}=\dfrac{1}{2}bcsin\widehat{BAC}=\dfrac{1}{2}.100.92.sin35^o=2760\left(cm^2\right)\)

\(S_{ABC}=\dfrac{1}{2}AH.BC\Rightarrow AH=\dfrac{2S}{BC}=\dfrac{2.2760}{58}=95,2\left(cm\right)\)