将⊿ADF顺时针旋转90度,D与B点重合,F旋转至点M,
则AM=AF,∠MAE=∠EAF=45°,AE=AE
∴⊿AME≌⊿AFE
∴EF=ME=BE+DF
∴△CEF的周长=EC+CF+EF
=EC+CF+BE+DF
=EC+BE+(CF+DF)
=BC+CD=2+2
=4
将⊿ADF顺时针旋转90度,D与B点重合,F旋转至点M,
则AM=AF,∠MAE=∠EAF=45°,AE=AE
∴⊿AME≌⊿AFE
∴EF=ME=BE+DF
∴△CEF的周长=EC+CF+EF
=EC+CF+BE+DF
=EC+BE+(CF+DF)
=BC+CD=2+2
=4