∠B=60°
∠BCA+∠BAC=120°
∠FCA+∠FAC=60°
∠CFA=120°
在AC上截取CM=CD
△CDF≌△CFM
∠DFC=∠CFM=60°
∠MFA=60°
∠EFA=60°
∠MFA=∠EFA
∠EAF=∠MAF
AF=AF
△AFE≌△MFA
AM=AE
AC=CM+AM=CD+AE
∠B=60°
∠BCA+∠BAC=120°
∠FCA+∠FAC=60°
∠CFA=120°
在AC上截取CM=CD
△CDF≌△CFM
∠DFC=∠CFM=60°
∠MFA=60°
∠EFA=60°
∠MFA=∠EFA
∠EAF=∠MAF
AF=AF
△AFE≌△MFA
AM=AE
AC=CM+AM=CD+AE