Hello,

The least number is 4.

Solution:

In order to make 572 a perfect square, we need to find the nearest square number to 572.

To find the nearest square number, take square root of 572, which gives the result as 23.917

So, the nearest square number to 572 is (24)^2 =576

Now, to calculate the least number, subtract 572 from 576,

So, the lowest number to be added to 572 is = 576 – 572 = 4

Hence, to make 572 a perfect square, 4 is to be added.

Hope this helps,

All the Best!!