B_1 = (11.385378275310622, -4.31061065321688)
B_2 = (12.629673268544714, -5.351755443473981)
C_1 = (9.963326854471642, -5.377149218846105)
O = (4.630634026325501, -0.323787919793333)
B_3 = (7.779462172468937, -2.7108028047730346)
c = Circle(O, B_3)
C_2 = (-1.0829654324025069, -1.9489895436092999)
D = (20.09544322794917, -1.771233116004428)
C = Point(c)
a_1 = Segment(O, C)
a = OrthogonalLine(C, a_1)
B = Point(a)
α = Angle(B, C, O)