Why do we consider $pi$ as a irrational number?












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Why do we consider $pi$ as a irrational number? Why is that? We all know that $pi$ is the solution of circumference / diameter of a circle and there could be infinite amount of circles which can have circumference and diameter in the form of positive integers? Then why is that?










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  • 3




    $begingroup$
    Because someone proved it.
    $endgroup$
    – Mauro ALLEGRANZA
    Jan 24 at 10:31








  • 1




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    We consider $pi$ as an irrational number because it is an irrational number.
    $endgroup$
    – Joel Reyes Noche
    Jan 24 at 10:34










  • $begingroup$
    Can you recall what an irrational number is? What is your definition of a circle? What do you call consider in mathematics? Can you give an example of a circle having integers for both circumference and diameter?
    $endgroup$
    – mathcounterexamples.net
    Jan 24 at 11:34
















-1












$begingroup$


Why do we consider $pi$ as a irrational number? Why is that? We all know that $pi$ is the solution of circumference / diameter of a circle and there could be infinite amount of circles which can have circumference and diameter in the form of positive integers? Then why is that?










share|cite|improve this question











$endgroup$








  • 3




    $begingroup$
    Because someone proved it.
    $endgroup$
    – Mauro ALLEGRANZA
    Jan 24 at 10:31








  • 1




    $begingroup$
    We consider $pi$ as an irrational number because it is an irrational number.
    $endgroup$
    – Joel Reyes Noche
    Jan 24 at 10:34










  • $begingroup$
    Can you recall what an irrational number is? What is your definition of a circle? What do you call consider in mathematics? Can you give an example of a circle having integers for both circumference and diameter?
    $endgroup$
    – mathcounterexamples.net
    Jan 24 at 11:34














-1












-1








-1





$begingroup$


Why do we consider $pi$ as a irrational number? Why is that? We all know that $pi$ is the solution of circumference / diameter of a circle and there could be infinite amount of circles which can have circumference and diameter in the form of positive integers? Then why is that?










share|cite|improve this question











$endgroup$




Why do we consider $pi$ as a irrational number? Why is that? We all know that $pi$ is the solution of circumference / diameter of a circle and there could be infinite amount of circles which can have circumference and diameter in the form of positive integers? Then why is that?







irrational-numbers rational-numbers pi






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share|cite|improve this question













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share|cite|improve this question








edited Jan 24 at 10:36









Servaes

27.4k34098




27.4k34098










asked Jan 24 at 10:30









Mad DawgMad Dawg

295




295








  • 3




    $begingroup$
    Because someone proved it.
    $endgroup$
    – Mauro ALLEGRANZA
    Jan 24 at 10:31








  • 1




    $begingroup$
    We consider $pi$ as an irrational number because it is an irrational number.
    $endgroup$
    – Joel Reyes Noche
    Jan 24 at 10:34










  • $begingroup$
    Can you recall what an irrational number is? What is your definition of a circle? What do you call consider in mathematics? Can you give an example of a circle having integers for both circumference and diameter?
    $endgroup$
    – mathcounterexamples.net
    Jan 24 at 11:34














  • 3




    $begingroup$
    Because someone proved it.
    $endgroup$
    – Mauro ALLEGRANZA
    Jan 24 at 10:31








  • 1




    $begingroup$
    We consider $pi$ as an irrational number because it is an irrational number.
    $endgroup$
    – Joel Reyes Noche
    Jan 24 at 10:34










  • $begingroup$
    Can you recall what an irrational number is? What is your definition of a circle? What do you call consider in mathematics? Can you give an example of a circle having integers for both circumference and diameter?
    $endgroup$
    – mathcounterexamples.net
    Jan 24 at 11:34








3




3




$begingroup$
Because someone proved it.
$endgroup$
– Mauro ALLEGRANZA
Jan 24 at 10:31






$begingroup$
Because someone proved it.
$endgroup$
– Mauro ALLEGRANZA
Jan 24 at 10:31






1




1




$begingroup$
We consider $pi$ as an irrational number because it is an irrational number.
$endgroup$
– Joel Reyes Noche
Jan 24 at 10:34




$begingroup$
We consider $pi$ as an irrational number because it is an irrational number.
$endgroup$
– Joel Reyes Noche
Jan 24 at 10:34












$begingroup$
Can you recall what an irrational number is? What is your definition of a circle? What do you call consider in mathematics? Can you give an example of a circle having integers for both circumference and diameter?
$endgroup$
– mathcounterexamples.net
Jan 24 at 11:34




$begingroup$
Can you recall what an irrational number is? What is your definition of a circle? What do you call consider in mathematics? Can you give an example of a circle having integers for both circumference and diameter?
$endgroup$
– mathcounterexamples.net
Jan 24 at 11:34










1 Answer
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$begingroup$

You say that




"there could be infinite amount of circles which can have circumference and diameter in the form of positive integers".




On the face of it, there could be. But it turns out that there is no circle which has both circumference and diameter in the form of a positive integer!



A first step in proving this, is to prove that the ratio of the circumference to diameter is the same for all circles. This ratio is called $pi$. It has long been proven that this ratio is irrational, though there is no proof (yet) that is as elementary as the definition of $pi$ itself. See the Wikipedia page for a few examples of proofs.






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    1 Answer
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    active

    oldest

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    1 Answer
    1






    active

    oldest

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    active

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    active

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    1












    $begingroup$

    You say that




    "there could be infinite amount of circles which can have circumference and diameter in the form of positive integers".




    On the face of it, there could be. But it turns out that there is no circle which has both circumference and diameter in the form of a positive integer!



    A first step in proving this, is to prove that the ratio of the circumference to diameter is the same for all circles. This ratio is called $pi$. It has long been proven that this ratio is irrational, though there is no proof (yet) that is as elementary as the definition of $pi$ itself. See the Wikipedia page for a few examples of proofs.






    share|cite|improve this answer









    $endgroup$


















      1












      $begingroup$

      You say that




      "there could be infinite amount of circles which can have circumference and diameter in the form of positive integers".




      On the face of it, there could be. But it turns out that there is no circle which has both circumference and diameter in the form of a positive integer!



      A first step in proving this, is to prove that the ratio of the circumference to diameter is the same for all circles. This ratio is called $pi$. It has long been proven that this ratio is irrational, though there is no proof (yet) that is as elementary as the definition of $pi$ itself. See the Wikipedia page for a few examples of proofs.






      share|cite|improve this answer









      $endgroup$
















        1












        1








        1





        $begingroup$

        You say that




        "there could be infinite amount of circles which can have circumference and diameter in the form of positive integers".




        On the face of it, there could be. But it turns out that there is no circle which has both circumference and diameter in the form of a positive integer!



        A first step in proving this, is to prove that the ratio of the circumference to diameter is the same for all circles. This ratio is called $pi$. It has long been proven that this ratio is irrational, though there is no proof (yet) that is as elementary as the definition of $pi$ itself. See the Wikipedia page for a few examples of proofs.






        share|cite|improve this answer









        $endgroup$



        You say that




        "there could be infinite amount of circles which can have circumference and diameter in the form of positive integers".




        On the face of it, there could be. But it turns out that there is no circle which has both circumference and diameter in the form of a positive integer!



        A first step in proving this, is to prove that the ratio of the circumference to diameter is the same for all circles. This ratio is called $pi$. It has long been proven that this ratio is irrational, though there is no proof (yet) that is as elementary as the definition of $pi$ itself. See the Wikipedia page for a few examples of proofs.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 24 at 10:33









        ServaesServaes

        27.4k34098




        27.4k34098






























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