I know what a perfect square is. It's the square of a whole number.
But I don't know what a perfect square root is. There's no reason why an exact square root has to be a whole number. Sure 3 is the exact square root of 9. But 2.5 is the exact square root of 6.25. and 3.1 is the exact square root of 9.61.
I'm not so sure that there is even such a thing as a perfect square root.
I could certainly be wrong.
