It is known that ab = AE, BC = ed, AF is the vertical bisector of CD, as shown in the figure

It is known that ab = AE, BC = ed, AF is the vertical bisector of CD, as shown in the figure

It is proved that connecting AC, ad, ∵ AF is the vertical bisector of CD, ∵ AC = ad, ab = AE, BC = ed, ≌ △ ABC ≌ △ AED (SSS). ∵ B = E