Question

Why we put the value of π-22/7

Answer 1

it is the approximate value of pie. While its actual value is 3.14..... and afterwards while we put it in fraction form it becomes 22/7

Answer 2

We know 22/7 can be written in the form 3.14, we know that pie is a irrational no. And answer for any irrational is non terminating non repeating so we can not take these much infinite values, so we simply take standard value it is just to make calculation easier.