α = 1.9024088846738192 rad (slider from 0 to 6.283185307179586, step 0.5*°)
β = 3.036872898470133 rad (slider from 0 to 6.283185307179586, step 0.25*°)
A = (5.26, -2.12)
B = (8.56, 2.3)
c = Circle(A, B)
r = Segment(A, B)
C: A + (r; α)
D: A + (r; β)
a = Segment(C, D)