Déplacer D et E à votre convenance pour vérifier 
que le parallélisme est nécessaire pour pouvoir
appliquer le théorème de Thalès

Déplacer I à votre convenance pour vérifier 
que le théorème de Thàlès est applicable
pour toutes positions de I sur (FG)\{F;G}

B = (0, 0)
C = (-5, -2)
A = (-6, 4)
b = Line(A, B)
E = Point(b)
distanceCB = Distance(C, B)
a = Line(A, C)
D = Point(a)
distanceDE = Distance(D, E)
nombre5: distanceCB / distanceDE
c = Segment(E, D)
d = Segment(B, C)
G = (10, 0)
H = (16, -1)
e = Segment(G, H)
F = (11, 4)
f = Segment(G, F)
g = Segment(F, H)
h = Line(F, G)
i = Line(F, H)
I = Point(h)
j = Line(I, e)
J = Intersect(j, i)
k = Segment(G, I)
l = Segment(H, J)
m = Segment(A, D)
n = Segment(C, D)
p = Segment(A, E)
q = Segment(A, B)
poly1, c_1, a_1, b_1 = Polygon(A, B, C)
poly2, d_1, a_2, e_1 = Polygon(A, E, D)
poly3, j_1, f_1, i_1 = Polygon(F, I, J)
poly4, g_1, f_2, h_1 = Polygon(F, H, G)
L = (4, -6)
K = (4, 12)
r = Segment(K, L)
distanceAB = Distance(A, B)
TexteAB: "\overline{" + (Name[A]) + (Name[B]) + "} \, = \, " + distanceAB
distanceAE = Distance(A, E)
TexteAE: "\overline{" + (Name[A]) + (Name[E]) + "} \, = \, " + distanceAE
distanceAC = Distance(A, C)
TexteAC: "\overline{" + (Name[A]) + (Name[C]) + "} \, = \, " + distanceAC
distanceAD = Distance(A, D)
TexteAD: "\overline{" + (Name[A]) + (Name[D]) + "} \, = \, " + distanceAD
distanceFG = Distance(F, G)
TexteFG: "\overline{" + (Name[F]) + (Name[G]) + "} \, = \, " + distanceFG
distanceFI = Distance(F, I)
TexteFI: "\overline{" + (Name[F]) + (Name[I]) + "} \, = \, " + distanceFI
distanceFH = Distance(F, H)
TexteFH: "\overline{" + (Name[F]) + (Name[H]) + "} \, = \, " + distanceFH
distanceFJ = Distance(F, J)
TexteFJ: "\overline{" + (Name[F]) + (Name[J]) + "} \, = \, " + distanceFJ
nombre1: distanceAC / distanceAD
nombre2: distanceAB / distanceAE
nombre3: distanceFG / distanceFI
nombre4: distanceFH / distanceFJ
text4: "\frac{AC}{AD}=" + nombre1
text3: "\frac{AB}{AE}=" + nombre2
TexteCB: "\overline{" + (Name[C]) + (Name[B]) + "} \, = \, " + distanceCB
TexteDE: "\overline{" + (Name[D]) + (Name[E]) + "} \, = \, " + distanceDE
distanceGH = Distance(G, H)
TexteGH: "\overline{" + (Name[G]) + (Name[H]) + "} \, = \, " + distanceGH
distanceIJ = Distance(I, J)
TexteIJ: "\overline{" + (Name[I]) + (Name[J]) + "} \, = \, " + distanceIJ
text5: "\frac{BC}{DE}=" + nombre5
nombre6: distanceGH / distanceIJ
text6: "\frac{FG}{FI}=" + nombre3
text7: "\frac{FH}{FJ}=" + nombre4
text8: "\frac{GH}{IJ}=" + nombre6