Question

why the value of pie is 22/7

Answer 1

That is an approximation. The actual pi is an irrational number, so it cannot be expressed as the ratio of two integers. The Wikipedia page also contains information on why some people believe pi to be 22/7. Thus, π is not equal to22/7 because it is in fact less than 22/7.

Answer 2

The fixed value of pie is 22/7 because it is used in taking out the perimeter and area of many things and if the value becomes different then the answer cannot come same