Question

如图,AB平行CD平行GH,EG平分∠BEF,FG平分∠EFD.试说明∠EGF=90°

Answer 1

证明：∵EG平分∠BEF∴∠BEG＝∠BEF/2∵FG平分∠EFD∴∠DFG＝∠EFD/2∵AB∥HG∴∠HGE＝∠BEF＝∠BEF/2 （两直线平行,内错角相等）∵CD∥HG∴∠HGF＝∠DFG＝∠EFD/2∵AB∥CD∴∠BEF+∠EFD＝180 （两直线平行,同旁内角...