4.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:-
It can be seen that 2 is the remainder. So we will subtract 2 from 402. So, the required number is 400 and its square root is 20.
(ii) 1989:-
It can be seen that 53 is the remainder here. So we will subtract 53 from 1989 in order to make it a perfect square.
The required number is 1936 and its square root is 44.
(iii) 3250:-
It can be seen that 1 is the remainder. So we will subtract 1 from 3250. So, the required number is 3249 and its square root is 57.
(iv) 825:-
It can be seen that 41 is the remainder. So we will subtract 41 from 825 to make it a perfect square number.
The required number is 784 and its square root is 28.
(v) 4000:-
It can be seen that 31 is the remainder here. So we will subtract 31 from 4000. So, the required number is 3969 and its square root is 63.