Question

For each of the following, find the least number that must be added so that the resulting number is a perfect square. 7172

• A. 23
• B. 65
• C. 15
• D. 53

Answer 1

Answer: (D)

53

Taking square root of $7172$, we find that $116$ has been left as shown below. Also, we see that $7172$ is greater than $(84{)}^2$

On adding the required number to $7172$, we get $(85{)}^2$ i.e., $7225$.

So, the required number is $7225-7172=53$

Hence, $53$ is the least number that must be added so that the resulting number is a perfect square.