∴AE∥CD,AE=CD,
EA = BA,
∴AB∥CD,AB=CD,
∴ quadrilateral ABCD is a parallelogram,
∴ad=bc;
(2) Solution: When ∠ e = 45, the quadrilateral ABCD is a square.
Quadrilateral ACDE is a parallelogram,
∴AC=DE,
BD = DE,
∴AC=DE,
∴? ABCD is rectangular,
BD = DE,
∴∠E=∠EBD=45,
∴∠BDE=90,
∫AC∑DE,
∴∠AFB=∠BDE=90,
∴AC⊥BD,
∴ quadrilateral ABCD is a square.