过A做AE⊥BC,交BC于E,过D做DF⊥BC,交BC于F
∵∠B = 45° ,AC⊥AB
∴△ABC是等腰Rt△
∵AE⊥BC
∴E是BC的中点,AE = BE =EC = BC/2 = 2√2
∵AD//BC,Ae⊥BC,DF⊥BC
∴DF = AE = 2√2
EF = AD = √2
∴CF = CE-EF=√2
∴在Rt△DFC中
CD = √(8+2) = √10
过A做AE⊥BC,交BC于E,过D做DF⊥BC,交BC于F
∵∠B = 45° ,AC⊥AB
∴△ABC是等腰Rt△
∵AE⊥BC
∴E是BC的中点,AE = BE =EC = BC/2 = 2√2
∵AD//BC,Ae⊥BC,DF⊥BC
∴DF = AE = 2√2
EF = AD = √2
∴CF = CE-EF=√2
∴在Rt△DFC中
CD = √(8+2) = √10