"Square numbers" have integer square roots. A square number that is divided by an even power of 10 will have an exact square root, too. Examples 25^2 = 625, so √625 = 25 (exactly) 625/(10^2) = 6.25, so √6.25 = 2.5 (exactly)
The ratio of two square numbers will have an exact square root. The root may have an infinitely repeating decimal fraction, but it can be expressed as an exact fraction or mixed number.
The ratio of two square numbers will have an exact square root. The root may have an infinitely repeating decimal fraction, but it can be expressed as an exact fraction or mixed number.