As shown in the figure, in ladder ABCD, AB is parallel to CD, ad = BC, EF are AD.BC BD bisection ∩ ABC is called EF at point G, eg = 18, FG = 10 to find the trapezoid perimeter

As shown in the figure, in ladder ABCD, AB is parallel to CD, ad = BC, EF are AD.BC BD bisection ∩ ABC is called EF at point G, eg = 18, FG = 10 to find the trapezoid perimeter

∵ f is the midpoint of BC, e is the midpoint of AD, AE = ed, BF = CF ∵ EF ∥ ab ∥ DC ∥ eg is the median line of △ abd, FG is the median line of △ BCD, ab = 2EG = 36dc = 2fg = 20 ∵ BD bisection ∥ ABC ∥ abd = ∥ DCB ∥ ab ∥ DC ∥ abd = ∥ BDC ∥ BDC = ∥ DCB ∥ BC = CD = 20 ∫ ad = BC = 20 ∥ ABCD perimeter = a