A_1 = (5.06, 1.7)
A_2 = (5.56, -1.08)
A_3 = (8.24, -2.08)
A_4 = (9.496178844287616, -1.0749074865529178)
A = (7.62, 2)
c = Conic(A_1, A_2, A_3, A_4, A)
R = Point(c)
S = (2, -4)
T = (17.92587113598539, -2.8205658357873307)
a = Line(S, T)
d_1 = Line(R, A_1)
d_2 = Line(R, A_2)
d_3 = Line(R, A_3)
d_4 = Line(R, A_4)
A'_1 = Intersect(a, d_1)
A'_2 = Intersect(a, d_2)
A'_3 = Intersect(a, d_3)
A'_4 = Intersect(a, d_4)
b = CrossRatio(A'_1, A'_2, A'_3, A'_4)
texte1: "\text{Birapport: b=\frac{\frac{\overline{A'_1A'_3}}{\overline{A'_1A'_4}}}{\frac{\overline{A'_2A'_3}}{\overline{A'_2A'_4}}}\approx " + (LaTeX[b]) + ""