Hi Pravesh,
We know that the length of the diagonal of the bigger square = $$2\sqrt{2}$$
It is also equal to the radius of bigger circle+ radius of smaller circle + the diagonal fo the smaller square.
The diagonal of the smaller square = $$r\sqrt{2}$$
Thus, $$2\sqrt{2} = 2 + r + r\sqrt{2}$$
Solving this we will get r = $$6 - 4\sqrt{2}$$

Hi Rohit,

The answer given in the solution is correct. It has to be option 4. Kindly share your method so that i can point out where you are going wrong. Hope it helps. Thanks

Hi Moitreyee,

Can you please be a bit more specific. What you did not understand in the solution.It will be easier for me to help you then. Thanks.