∵∠ABC = 45°,CD⊥AB∴CD = DB∵BE⊥AC,∠CFE = ∠DFB∴∠ACB = ∠FBD∴△ADC≌△FDB∴AC = BF∵EB是∠ABC的角平分线,EB⊥AC∴△ABD是等腰三角形,AB=AC∴E是AC的中点∴CE =AC/2∵AC = BF∴CE = BF/2 第三题不知道...