r = 10 (slider from 0 to 10, step 0.1)
c: x^(2) + y^(2) = r^(2)
x_1 = 8.4 (slider from 5 to 21, step 0.1)
d: (x - x_1)^(2) + y^(2) = r^(2)
A = (0, 0)
B: (x_1, 0)
a = Segment(A, B)
b = Segment(A, B)
C = Intersect(c, d, 1)
D = Intersect(c, d, 2)
e = Line(C, D)