The problem is, to most reading your question it looks exactly like a duplicate, and on top of that it looks like very little time was spent when you wrote it. (Compared to the other question)
Perhaps if you had said "I tried searching for an answer, but I didn't really understand the ones I found," then it wouldn't of been closed. If you had just said something that indicated you searched even a little before posting your question, then it would have been a different case.
Edit: I continue: A quick Google search of your question found this webpage which deals with your question.
Also, when you imputed your original question, "Why is Pi a constant?" MSE suggests posts that have already been made. I tried this, and the second one it suggested was this which deals exactly with your question. Now again, perhaps this doesn't give the answer you want, but then you should of at least mentioned in your question that you had already looked at it.