已知如圖AB=AC AD=AE BD=CE求證

已知如圖AB=AC AD=AE BD=CE求證


證明:
∵AB=AC,AD=AE,BD=CE
∴△ABD≌△ACE(SSS)
∴∠BAD=∠CAE
∴∠BAD-∠CAD=∠CAE-∠CAD
即∠BAC=∠DAE



已知:如圖,AD=AE,AB=AC,∠DAE=∠BAC.求證:BD=CE.


證明:∵∠DAE=∠BAC,∴∠DAE-∠BAE=∠EAC-∠BAE,∴∠BAD=∠CAE,在△BAD和△CAE中,AD=AE∠BAD=∠CAEAB=AC,∴△BAD≌△CAE(SAS),∴BD=EC.



已知:如圖,AB=AC,AD=AE,∠BAC=∠DAE,求證:BD=CE.


證明:∵∠DAE=∠BAC,∴∠DAE-∠BAE=∠EAC-∠BAE,∴∠BAD=∠CAE,在△BAD和△CAE中,AD=AE∠BAD=∠CAEAB=AC,∴△BAD≌△CAE(SAS),∴BD=EC.