As shown in the figure, △ ABC, ad is the angular bisector, e and F are the points on AC and ab respectively, and ∠ AED + ∠ AFD = 180 °. What is the relationship between de and DF, and explain the reason

As shown in the figure, △ ABC, ad is the angular bisector, e and F are the points on AC and ab respectively, and ∠ AED + ∠ AFD = 180 °. What is the relationship between de and DF, and explain the reason

The reason is: DM ⊥ AB in M, DN ⊥ AC in N, ∵ ad bisection ﹥ BAC, ∵ DM = DN, ∵ FMD = ﹥ end = 90 °, ∵ AED + ﹥ AFD = 180 °, ﹥ AED + ﹥ den = 180 °, ﹥ MFD = ﹥ den, in △ FMD and △ end, ﹥ MFD = ﹥ den ﹥ FMD = ﹥ enddm = DN ≌ FMD ≌ end