r_1 = 0.8 (slider from 0 to 5, step 0.1)
C_1 = (1, 0)
P = (1.1702999433110313, 1.0648710610936594)
C_f = (0, 0)
a = Ray(C_f, P)
c = Circle(C_1, r_1)
PP_1, P_1 = Intersect(c, a)