45度
角EAB+角FBA=180+180-90=270度
所以角DAB+角DBA=270/2度=135度
角D=180-角DAB-角DBA=45度
45度,180-∠eab+180-∠abf=90相当于360-2∠dab-2∠dba=90相当于180-∠dab-∠dba=45
∠EAB+∠BAC+∠ABF+∠ABC=2*180
(∠EAB+∠ABF)+(∠BAC+∠ABC)=360
(2∠DAB+2∠DBA)+90=360
2(∠DAB+∠DBA)=270
2(180-∠D)=270
2∠D=90
∠D=45
∠EAB+∠BAC+∠ABF+∠ABC=2*180(∠EAB+∠ABF)+(∠BAC+∠ABC)=360(2∠DAB+2∠DBA)+90=3602(∠DAB+∠DBA)=2702(180-∠D)=2702∠D=90∠D=45