[tex]\widehat{E}=90^{\circ}[/tex]
[tex]\Rightarrow \widehat{C}=\widehat{E}=45^{\circ}[/tex]
[tex]\widehat{D}=90^{\circ}\Rightarrow \widehat{A}=\widehat{B}=45^{\circ}[/tex]
-Có:[tex]\widehat{EAC}+\widehat{CAB}+\widehat{DAB}=180^{\circ} \Rightarrow \widehat{BAC}=90^{\circ}[/tex]