Question

求解，学霸

Answer 1

作MF∥AB   则MF⊥EC   EG＝GC﹙∵AM＝MD﹚     连接MC   △MGE≌△MGC﹙SAS﹚

∠CMG＝∠EMG＝∠MEA      ∠DMC＝∠DME-∠CME＝3MEA-2MEA＝∠MEA

∠DCM＝∠CMG＝∠MEA＝∠DMC    DC＝DM＝MA    ∴BC＝AD＝2DC＝2AB