.如图,AB∥CD,AE平分∠BAD,CD与AE相交于F,∠CFE = ∠E,求证AD∥BC.
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证明:∵AE平分∠BAD
∴∠1 = ∠2
∵AB∥CD
∴∠1 = ∠CFE
∵∠CFE = ∠E
∴∠2 = ∠E
∴AD∥BC