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M在BA延长线上(A的上方),N在DC延长线上(C的下方),(1),平行四边形ABCD,AB‖DC,∠MAD=∠ADC,[内错角];AD‖BC,∠ADC=∠BCN,[同位角];所以∠MAD= ∠BCN;∠MAD/2= ∠BCN/2;∠EAD= ∠BCF;同理,∠EDA= ∠FBC;所以∠AED=180°-∠EAD- ∠EDA=180°-∠BCF- ∠FBC=∠BFC;(2)AE, ED, BF, FC, EC, HF?应该是AE, ED, BF, FC, EG, HF!AD=BC,∠EAD= ∠BCF;∠EDA= ∠FBC;△AED≌△CFB,[ASA],所以,AE=FC,ED=BF,ED=BF,∠EDA= ∠FBC,∠EGD= ∠EHC=∠BHF,所以∠GED= ∠HFB,△EDG≌△FBH,[ASA],故,EG=FH |
