Los triángulos ADD' y BCC' son congruentes.

Como AD || BC y AD' || BC', se deduce que DD' || CC'.

A = (-0.6794439111577026, 7.591984164079004)
B = (4.31437988129093, 6.2892475225706646)
C' = (8.521133619494941, 7.700545550871365)
c = Line(A, B)
e = Line(B, C')
f = Line(A, e)
g = Line(C', c)
D' = Intersect(f, g)
poly1, h, i, j, k, C, D = Polygon(A, B, 4)
poly2, d_1, e_1, f_1, g_1 = Polygon(A, B, C', D')
l = Line(D, D')
s = Line(C, C')
α = Angle(C, B, A)
β = Angle(B, A, D)
γ = Angle(A, D, C)
δ = Angle(D, C, B)