O = (6.446, -0.239)
B = (4.1954, 2.2536)
c = Circle(O, B)
A = Point(c)
C = Mirror(A, O)
a = Segment(B, A)
b = Segment(B, C)
d = Segment(C, O)
e = Segment(O, A)
f = Segment(B, O)
α = Angle(O, A, B)
β = Angle(A, B, O)
γ = Angle(O, B, C)
δ = Angle(B, C, O)