Dreieck

x_{1} = 10 (slider from 0 to 15)
M: (0, 0)
A: ((-x_{1}), 0)
C: (0, x_{1})
d1, c, x_4, b = Polygon(C, M, A)
B: (x_{1}, 0)
d2, x_3, x_2, a = Polygon(C, M, B)
α = Angle(M, A, C)
β = Angle(C, B, M)
γ = Angle(A, C, M)
δ = Angle(B, M, C)