Propriété des triangles semblables par Thalès

C = (2.4058852735535132, -1.4022903507801037)
A = (2.8970417569342786, 2.868635591661336)
B = (-1.6942036311902693, 0.7972365095772378)
f = Segment(C, B)
g = Segment(B, A)
h = Segment(A, C)
α = Angle(A, C, B)
β = Angle(B, A, C)
γ = Angle(C, B, A)
etape = 3 (slider from 0 to 3, step 1)
D = Point(g)
E = Point(h)
a = Line(E, D)
η = Angle(E, D, A)
θ = Angle(A, E, D)
F = Point(a)
ι = Angle(F, D, B)
b = Line(E, F)
e = Line(C, B)
f_1 = Segment(E, D)