1)作BH⊥AC,交AC于H.
∵∠ABH+∠BAC=90°,∠CAD+∠BAC=90°.
∴∠ABH=∠CAD.
∵AB=AC,∠AHB=∠ADC=90°.
∴△ABH≌△CAD.∴BH=AD.
∵AE=AD,∴BH=AE.
∵∠BHF=EAF=90°,∠BFH=∠AFE.
∴△BFH≌△EFA.
∴BF=EF.
2)连接CE.
∵AB=AC,∠BAD=∠CAE=90°,AD=AE.
∴△ABD≌△ACE,∴BD=CE.
∵BF=EF,BM=CM.
∴FM=1/2CE.
∴FM=1/2BD
1)作BH⊥AC,交AC于H.
∵∠ABH+∠BAC=90°,∠CAD+∠BAC=90°.
∴∠ABH=∠CAD.
∵AB=AC,∠AHB=∠ADC=90°.
∴△ABH≌△CAD.∴BH=AD.
∵AE=AD,∴BH=AE.
∵∠BHF=EAF=90°,∠BFH=∠AFE.
∴△BFH≌△EFA.
∴BF=EF.
2)连接CE.
∵AB=AC,∠BAD=∠CAE=90°,AD=AE.
∴△ABD≌△ACE,∴BD=CE.
∵BF=EF,BM=CM.
∴FM=1/2CE.
∴FM=1/2BD