∴AB∥CD,AD=BC,AB=CD

∴∠ADE=60 =∠CBF

AE = AD，

Delta ade is an equilateral triangle.

∴AD=AE=DE

Similarly CB=CF=BF.

∴AB+BF=CD+DE

That is AF=CE.

∫AB∨CD

∴ Quadrilateral AFCE is a parallelogram.

2. The quadrilateral ABCD is a diamond.

∴AD=CD=DE

∴S△ADE=S△ADC

Similarly, S△ABC=S△FBC.

∴ area of quadrilateral AFCE =2× area of quadrilateral ABCD =2×2× radical number 3=4 radical number 3