Tổng của hai góc α và β luôn bằng 180°

B_1 = (14.610920129870127, -4.341525792207788)
B_2 = (30.41642838215584, -7.347980606207792)
O = (8.638375929012986, -1.5620623802077935)
C_1 = (12.663362521012985, -6.73704514135065)
c = Circle(O, C_1)
A = Point(c)
D = Point(c)
C = Point(c)
B = Point(c)
a = Segment(A, D)
b = Segment(D, C)
d = Segment(C, B)
e = Segment(B, A)
α = Angle(D, A, B)
β = Angle(B, C, D)
E = (36.633595171584375, -4.329240662207793)
F = (27.397688438155836, -4.257365901636365)
f = Segment(E, F)
E' = Rotate(E, α, F)
F' = Rotate(F, α, F)
f' = Segment(E', F')
E'' = Rotate(E', β, F)
F'' = Rotate(F', β, F)
f'' = Segment(E'', F'')
γ = Angle(E, F, E')
δ = Angle(E', F, E'')