Answer: The radius of the small circle is about 0.85 cm - 0.95 cm
Explanation: I am not completely sure but I drew the same figure with the same lengths as given and between both circles there is almost a gam of 2.5 - 3 cm and when we draw a circle between them the diameter is about 1.7 - 1.9 so dividing the diameter by 2 to get the radius we get 0.85 cm - 0.95 cm.