Happy Pi day folks ! Heres a general misconception im having. It might turn out to be a pretty easy question so please do help me. If i pull out my compass to a radius of 7 cm and draw a circle on a paper. Then i'll take a piece of thread and cut it such that it matches exactly with the circle on paper and take the length of that particular thread and divide by 14cm, should i get the value of pi ? If its so, why isnt pi an irrational number. After all im dividing the circumfrence i've got by 14 cm. So it should a rational number. For example, if the circumfrence is 50.123456 cm ( i've not measured yet just an example) And i divide it by 14cm I shall get 50123456/14000000 as value of pi, which is supposedly rational ? Is it an contradiction ?