Đg vội lm tắt nhé :>
Xét ∆ABC có
A + B + C = 180° (đl tổng 3 góc...)
=> B + C = 80°
=> 2 C + 10° = 80°
=> C = 35°
=> B = 45°
Vậy...
Ta có :\(\Delta ABC\) có \(\widehat{A}=100^o\)
\(\widehat{B}+\widehat{C}=180^o-100^o=80^o\)
\(\Rightarrow\widehat{B}=\left(80^o+10^o\right):2=45^o\)
\(\widehat{C}=80^o-45^o=35^o\)
Ta có:
\(\widehat{A}+\widehat{B}+\widehat{C}=180^0\)
⇒1000+\(\widehat{C}\)+100+\(\widehat{C}\)=1800
⇒ 2.\(\widehat{C}\)=700
⇒ \(\widehat{C}\)=350
⇒ \(\widehat{B}\)=450
Vậy...