We know that there are two pie to get the perimeter and area of a circle (i.e 22/7 and 3.14 ) and we use different value to solve different numbers then how we know that where to use which value with the help of length of radius , diameter etc. .And as we know rational number means p/q where q not equal to zero then why 22/7 is not considered as a rational number.



22/7 is considered as the value of pie. it is just an assumption. even the great mathematicians couldn't tell the correct value of pie even for today. so , 22/7 is just taken as an assumption
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Because it is a non terminating and non recurring decimal
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