设AE和DC交点F。先把已知能算出来的列给你，自己算出来。∠AEC=140,∠ACD=10,∠ADC=70,∠ABC=∠ABE60.∠DFE=150.∠ADC=70.把∠EDC看成X吧，我够打。∠AED看成Y。∠DEB看成Z.推出:X+Y+∠DFE=180. Y+Z+∠BAE+∠ABE=180. 180-∠ABE-Z=180-∠ADC-X 算出X=20。就是∠EDC=20
