(1)证明:∵AB∥CD,∴∠1=∠2,
又∵∠BFE=∠C,∠BFE+∠BFA=∠C+∠EDA
∴∠BFA=∠ADE,∴△ABF∽△EAD.
(2)在Rt△ABE中,∠1=30°,
由正弦定理得:[AE/sin90°]=[AB/sin60°],
∴AE=[4/sin60°]=
8
3
3,
又[BF/AD]=[AB/AE],∴BF=[AB/AE]•AD=
3
3
2.
(1)证明:∵AB∥CD,∴∠1=∠2,
又∵∠BFE=∠C,∠BFE+∠BFA=∠C+∠EDA
∴∠BFA=∠ADE,∴△ABF∽△EAD.
(2)在Rt△ABE中,∠1=30°,
由正弦定理得:[AE/sin90°]=[AB/sin60°],
∴AE=[4/sin60°]=
8
3
3,
又[BF/AD]=[AB/AE],∴BF=[AB/AE]•AD=
3
3
2.