That refers to the positive root, at least if you take the root of a positive number. For example, 25 has two square roots - two numbers which, when squared, give 25. The positive one (+5) is called the principal square root (or 2nd. root).
Chat with our AI personalities
The principal square root is the non-negative square root.
The principal (positive) square root of 225 is 15.
You seem to be unaware of the fact that you can obtain the answer easily by using the scientific calculator that comes as part of your computer. In general the nth root is extremely difficult to find.
The principal square root of 9, the positive integer which is the square root of the number, is 3.
The principal (square) root of 10 is an irrational real number which equals approximately 3.16227766.