Hi, I think you mean "the square-root of pi"
Pi is the irrational number 3.14159265.... (pi is defined to be the number you get if you divide the circumference of a circle by its diameter, the preceding is an approximate decimal representation)
Now you can find the square root of pi by using a calculator and either using the square root key, or by taking pi "to the one-halfth power" as in:
The answer is about: 1.77245384989...
Just round this depending on how many digits you need; for example it is 1.8 to the nearest tenth, or 1.77 to the nearest 1/100, and so forth.