ABCDAE的精選

問題詳情：如圖,已知AB=CD,AE⊥BD,CF⊥BD,垂足分別爲E,F,BF=DE.求*:AB∥CD.【回答】解:∵AE⊥BD,CF⊥BD,∴∠AEB=∠CFD=90°.∵BF=DE,∴BE=DF.在Rt△AEB和Rt△CFD中,∴Rt△AEB≌Rt△CFD(HL),∴∠B=∠D,∴AB∥CD.知識點：...