O = (79.44173167150971, 57.07855791512799)
B = (117.14998662736197, 56.99499970180568)
a = Line(O, B)
C = (172.12606860509987, 124.29330695041588)
b = Segment(O, C)
D = Point(a)
α = Angle(D, O, C)