THAT IS,
we can express more correctly than using 3.14 as the circular constant.
Now in the whole world,
many mathematicians are competing hardly
to calculate the circular constant, I heard.
So, I do not know the exact calculated orders of the value of π,
we can understand that numbers of π under its decimal point exist forever.
I heard that π's more than 12 billions numbers is cleared.
Although I also explained it in 17. What are significant digits?
in a category of high school matters,
in cases of numbers using in math,
when we say 5, for example,
numbers to its hundred billion hundred billion decimal place
and its continued places must be 0.
So, if we said 3.14, it means 3.140000000000000...
In this situation, we can never say, "we said correct."
And it is not a correct expression of the circular constant,
which continue forever like 3.14159 26535 89793 23846 26433 83279 50288...
Human do not know the exact value of the circular constant
with the infinite number of numbers under its decimal point.
But if we only say πcm as the length of circumference with its radius 0.5cm, our expression with π is not a wrong expression.
In this case,
we use one of skills of "not saying incorrect matters",
such as "Avoiding incorrect expressions to express correctly."
I think, people who have this question are not trapped in this topic.
For example,
If we say the length of circumference with its radius 5
as 5x2x3.14=31.4,
we feel that we somehow understand that length in a concrete number.
But we lack a feeling of 5 times of a circle with its radius 1.
And, the length of circumference with its radius 1 is 2π.
But we can compere any circles with the standard circle (its radius is 1)
like that the length of circumference with its radius 5 is 10 π
and 5 times of it.
If you understand such viewings added,
you may feel its necessities as your feelings.
