As shown in the figure, it is known that de ∥ BC, DF and be are divided into ∥ ade and ∥ ABC equally, and it is proved that ∥ FDE = ∥ DEB

As shown in the figure, it is known that de ∥ BC, DF and be are divided into ∥ ade and ∥ ABC equally, and it is proved that ∥ FDE = ∥ DEB

It is proved that: ∵ de ∥ BC, ∵ ade = ∠ ABC (two lines are parallel and the same position angle is equal), and ∵ DF and be divide ∵ ade and ∵ ABC equally, ∵ ADF = ∵ DBE (two lines are parallel and the same position angle is equal), and ∵ DF ∥ be, ∵ FDE = ∵ DEB (two lines are parallel and the same inner stagger angle is equal)