1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Are my postulates true regarding circles?

  1. Nov 8, 2012 #1
    If we know the exact radius of a circle, then we can't have an exact circumference, and if we know the exact circumference, then we can't know the exact radius.

    If these postulates are true, then I realize that this idea is not original but probably known since B.C.
  2. jcsd
  3. Nov 8, 2012 #2
    Exact isn't the right word to use. If I have a circle with diameter 1, I know that the circumference is exactly ##\pi##, I just can't represent ##\pi## by a finite decimal sequence.

    However you are right in your idea, a circle cannot simultaneously have a rational circumference and a rational radius.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook