Question

如图,已知在△ABC中,BD=DC,∠1=∠2,求证；AD平分∠BAC

Answer 1

BD=BC=>∠DBC=∠DCB

∠1=∠2 =>∠ABC=∠ACB=>AB=AC

∠DBC=∠DCB =>△ABD≌△ACD

BD=CD

=>∠BAD=∠CAD=>AD平分∠BAC