If an inequality is given, and all numbers and expressions are positive, the inequality still holds for the square root of both sides. $$9<16\Rightarrow \sqrt{9}<\sqrt{16}$$ This operation can also be performed when solving inequalities. However, it must be known that the variable is positive. Thus for $r^2<14$ and $r>0$ the following yields. $$r<\sqrt{14}$$