c^2 = a^2 + b^2 - 2 \cdot a \cdot b \cdot cos(γ)

A = (5.39799079999999, -9.500194200000026)
B = (16.059566999999976, 0.83928)
c = Segment(A, B)
C = (21.986243799999972, -9.629035000000025)
b = Segment(A, C)
a = Segment(B, C)
α = Angle(C, A, B)
β = Angle(A, B, C)
γ = Angle(B, C, A)
f = OrthogonalLine(A, a)
D = Intersect(f, a)
h = Segment(D, A)
v = Segment(D, C)
δ = Angle(h, a)