如图,AB∥DC,AE⊥BD,CF⊥BD,BF=DE.求证:AE=CF.
证明∵AB∥DC,
∴∠1=.
∵AE⊥BD,CF⊥BD,
∴∠AEB=
∵BF=DE,
∴BF﹣EF=DE﹣EF
∴=.
∴△ABE≌△CDF.
∴AE=CF