Théorème d'Al Kashi
Author: Yvan Monka - m@ths et tiques 2013

a²=

b²=

c²=

cos(A)=

b²+c²-2bc x cos(A)=

A = (-1.236, 0.772)
B = (4.242, 0.728)
C = (3.054, 4.776)
poly1, c, a, b = Polygon(A, B, C)
α, β, γ = Angle(poly1)
B1: a^(2)
B3: b^(2)
B4: c^(2)
B5: cos(α)
B6: B3 + B4 - 2 * b * c * B5