Least number to be added to make 7399 is a perfect square

The least number to be added to 435 to make it a perfect square is?

What is the least number to be added to 8200 to make it a perfect square?

What is the least number to be added to 7700 to make it a perfect square? (a) 77 (b) 98 (c) 131 (d) 221 (e) None of these

What least number must be added to 526 to make it a perfect square ?

What least number must be added to 521 to make it a perfect square ?