A = (-0.92, 0.66)
B = (2.6, 3.86)
A' = Rotate(A, 90°, B)
α = Angle(A, B, A')
a = Line(A, B)
b = Line(B, A')
C = Point(b)
c = Segment(A, C)
d = Segment(A, B)
e = Segment(B, C)
β = Angle(C, A, B)
γ = Angle(B, C, A)