Cách làm cho bạn:
Ta có:
$ \widehat{A1}+\widehat{B}+\widehat{ADB}=\widehat{A2}+\widehat{C}+\widehat{ADC}=180^{\circ}$
Mà $\widehat{A1}=\widehat{A2}; \widehat{ADB}=80^{\circ}$ và $\widehat{B}=1,5\widehat{C}$
=>$1,5\widehat{C}+80=\widehat{C}+100$
=> $\widehat{C}=40^{\circ}$
=> $\widehat{B}=60^{\circ}$; $\widehat{A}=80^{\circ}$
Bình luận