Question

Bài 2

Cho tam giác ABC; A = 100 độ

B-C = 50 độ

Tính B; C

Answer 1

Trong \(\Delta ABC\) có : \(\widehat{A}+\widehat{B}+\widehat{C}=180^0\)

\(\Rightarrow\widehat{B}+\widehat{C}=180^0-\widehat{A}=180^0-100^0=80^0\) ​

Ta lại có : \(\widehat{B}-\widehat{C}=50^0\) ​

\(\Rightarrow\left\{{}\begin{matrix}\widehat{B}+\widehat{C}=80^0\\\widehat{B}-\widehat{C}=50^0\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}\widehat{B}=65^0\\\widehat{C}=15^0\end{matrix}\right.\)