如图,已知AB=AC,AD=AE,BD=CE.试说明:∠BAC=∠DAE

问题描述:

如图,已知AB=AC,AD=AE,BD=CE.试说明:∠BAC=∠DAE

证明
∵AB=AC,AD=AE,BD=CE
∴ΔBAD≌ΔCAD(三组对边分别相等的三角形全等)
∴∠BAD=∠CAD
∠BAC=∠BAD+∠DAC
=∠CAD+∠DAC
=∠DAE
证毕!