(1)证明:如图.
∵四边形ABCD是菱形,
∴AD ∥ BC.
∴∠1=∠2,
又∵∠B=∠AED,
∴△ABE ∽ △DEA.
(2)∵△ABE ∽ △DEA,
∴
AE
DA =
AB
DE ,
∴AE•DE=AB•DA.
∵四边形ABCD是菱形,AB=4,
∴AB=DA=4.
∴AE•DE=AB 2=16.
(1)证明:如图.
∵四边形ABCD是菱形,
∴AD ∥ BC.
∴∠1=∠2,
又∵∠B=∠AED,
∴△ABE ∽ △DEA.
(2)∵△ABE ∽ △DEA,
∴
AE
DA =
AB
DE ,
∴AE•DE=AB•DA.
∵四边形ABCD是菱形,AB=4,
∴AB=DA=4.
∴AE•DE=AB 2=16.