(MN)//(BC)
M' symétrique de M par rapport à A
N' symétrique de N par rapport à A

\frac{AN}{AC} =

\frac{AM}{AB} =

\frac{MN}{BC} =

AM = 

AB =

AN = 

AC =

MN =

BC =

A = (4.36, 0.18)
B = (9.6, 2)
a = Line(A, B)
C = (12, -2)
b = Line(A, C)
c = Line(B, C)
N = Point(b)
d = Line(N, c)
M = Intersect(a, d)
N' = Mirror(N, A)
M' = Mirror(M, A)
e = Line(M', N')
poly1, a_1, m, n = Polygon(M, N, A)
poly2, c_1, a_2, b_1 = Polygon(A, B, C)
r1: Distance[M, A] / Distance[A, B]
r2: Distance[A, N] / Distance[C, A]
T3: r2 + ""
T5: r1 + ""
r3: Distance[M, N] / Distance[C, B]
T7: r3 + ""
T9: n + ""
T11: c_1 + ""
T13: m + ""
T15: b_1 + ""
T18: a_1 + ""
T19: a_2 + ""