As shown in the figure, the quadrilateral ABCD is a rectangle, ∠ EDC = ∠ cab, ∠ Dec = 90 ° (1) verification: AC ‖ de（ 2) Make BF ⊥ AC at point F through point B, connect EF, try to judge the shape of quadrilateral BCEF, please explain the reason (do not judge parallelogram)

As shown in the figure, the quadrilateral ABCD is a rectangle, ∠ EDC = ∠ cab, ∠ Dec = 90 ° (1) verification: AC ‖ de（ 2) Make BF ⊥ AC at point F through point B, connect EF, try to judge the shape of quadrilateral BCEF, please explain the reason (do not judge parallelogram)

(1) ∵ ABCD is a rectangle, ∵ CDA = ∵ AB = 90 °,
∴∠CAB+∠DAC=90°,
∵∠EDC=∠CAB,∴EDC+∠DAC=90°,
∴∠CDA+∠EDC+∠DAC=180°,
That is, EDA + DAC = 180 °,
The two lines are parallel
(2) ABCD is a rectangle, DC = ab,
In Δ EDC and Δ fab,
DC=AB,∠EDC=∠CAB,∠DEC=∠AFB=90°,
∴ΔEDC≌ΔFAB,∴DE=AF,
A quadrilateral efad is a parallelogram,
The ad and EF are parallel and equal,
∵ AD and BC are parallel and equal,
The EF and BC are parallel and equal,
A quadrilateral BCEF is a parallelogram