Lemme du chevron :
aire (abd)/aire(acd)= a'b/a'c

a = (-2.589798657718123, -1.4871664167916039)
b = (-3.237315436241612, -2.808425787106446)
c = (-1.3753020134228229, -3.0415892053973006)
poly1, c_1, a_3, b_2 = Polygon(a, b, c)
d = (-2.6638926174496667, -2.3550524737631178)
poly2, d_1, a_1, b_1 = Polygon(a, b, d)
poly4, c_2, a_2, d_2 = Polygon(a, d, c)
e = Line(a, d)
a' = Intersect(e, a_3)