B = (0, 0)
k = Circle(B, 1)
A = Point(Circle[B, 1])
c = Segment(B, A)
h = OrthogonalLine(A, xAxis)
C_1 = Intersect(h, xAxis)
b_1 = Segment(A, C_1)
a_1 = Segment(C_1, B)
β = Angle(xAxis, c)
C: (a_1, 0)
a = Segment(B, C)
b = Segment(C, A)
β_1 = Angle(A, B, C_1)