r = 3.6 (slider from 0 to 6, step 0.1)
P = Point(xAxis)
Q = Point(xAxis)
c: (1.0 * 1.0 * 1.0 x - x(P))^(2.0) + 1.0 * 1.0 * 1.0 y^(2.0) + (1.0 * 1.0 * 1.0 x - x(Q))^(2.0) + 1.0 * 1.0 * 1.0 y^(2.0) = 2.0 * r^(2.0)
C = Point(c)
a = Segment(P, C)
b = Segment(Q, C)