O = (11.78, 6.72)
c = Circle(O, 10)
A = Point(c)
B = Point(c)
a = Ray(O, A)
b = Ray(O, B)
α = Angle(a, b)
β = Angle(b, a)
C = Point(c)
d = Ray(C, A)
e = Ray(C, B)
γ = Angle(d, e)
D = Point(c)
f = Ray(D, A)
g = Ray(D, B)
δ = Angle(f, g)