Find the least number which must be added to 6203 to obtain a perfect square.

Using the long division method:

Thus, to get a perfect square greater than the given number, we take the square of the next natural number of the quotient, i.e. 78.

$79^{2}=6241$

Number that should be added to the aiven number to make it a perfect square $=6241-6203$

= 38

The perfect square thus obtained is 6241 and its square root is 79.