Find the least number which must be subtracted from each of the following numbers so as to get a perfect square. Also find the square root of the perfect square so obtained.

**(i)** 402

**(ii)** 1989

**(iii)** 3250

**(iv)** 825

**(v)** 4000

**(i)** 402

**(ii)** 1989

**(iii)** 3250

**(iv)** 825

**(v)** 4000