Question

AB‖CD,EG平分∠BEF,FG平分∠EFD,求证,∠EGF=90°求证;∠EGF=90°

Answer 1

∵AB‖CD

∴∠BEF+∠EFD=180

∠GEF=∠BEF/2

∠EFG=∠EFD/2

∴∠GEF+∠EFG=90

∴∠EGF=90