There is no test case r < 1. For example, checkio("(1,2),(1,1),(2,1)") = '(x-1.5)^2+(y-1.5)^2=0.71^2'. Of course, correct answer is not '(x-1.5)^2+(y-1.5)^2=0.707^2'. The '{.3g}' trick does not work. Or it is easy to change condition to 1 <= r < 10.