Question

已知:如图,CD⊥AB,BE⊥AC,垂足分别为点D,E;又BE,CD相交于点F,且AF平分∠DFE求证AB=AC

Answer 1

解∵AF平分∠DFE,∴∠CAF=∠BAF,∴EF=DF,∵CD⊥AB,BE⊥AC,AF=AF,

∴Rt△ADC≌Rt△AEB,∴AB=AC