bạn tự vẽ hình nha
trên tia AM lấy MO sao cho AM=MO
CM [tex]\Delta EMO=\Delta DMA(c.g.c)[/tex]
[tex]\Rightarrow \widehat{O}=\widehat{MAD}[/tex]
Vì [tex]\widehat{OFD}=\widehat{ADF}\Rightarrow \widehat{OEA}=\widehat{AED}+\widehat{ADE}[/tex] [tex]\Rightarrow \widehat{OEA}=180-\widehat{DAE}[/tex]
Vì[tex]\widehat{EAD}+\widehat{DAC}=90; \widehat{EAD}+\widehat{EAB}=90[/tex]
[tex]\Rightarrow \widehat{EAB}+\widehat{EAD}+\widehat{DAC}=180-\widehat{EAD}\Rightarrow \widehat{BAC}=180-\widehat{EAD} \Rightarrow \widehat{OEA}=\widehat{BAC}[/tex]
[tex]\Rightarrow \Delta BAC=\Delta OEA\Rightarrow \widehat{O}=\widehat{B}[/tex]
Vì [tex]\widehat{MAD}+\widehat{BAM}=90[/tex] mà [tex]\widehat{MAD}=\widehat{B}\Rightarrow \widehat{B}+\widehat{BAM}=90[/tex]
Phần còn lại bạn làm tiếp nhé