EF and AB are connected in parallel, ce = cf

Angle ACD= angle BCD

CD gong * * *

CDE consistent CDF (SAS)

DE=DF

For DM above 2d, the vertical AC is AC and the vertical AC is M..

Cross d, DN, vertical BC, horizontal BC to n

From 1: DM=DN

Angle AMD= angle BND

Angle EDM= = angle FDN

EDM congruent FDN

DE=DF