Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Finding the diameter of a tube

  1. Jun 4, 2005 #1
    How can you find the diameter of a tube without measuring it? Is there a equation or something or any method other than measuring it
  2. jcsd
  3. Jun 4, 2005 #2
    If you know the cross sectional area, A of the tube, you can use

    [tex]A = \pi \left(\frac{D}{2}\right)^2[/tex] and solve for D.

    Other than that, no.

    Edit: if you know the circumference of the circle, C: [itex]C = \pi D[/itex].
    Last edited: Jun 4, 2005
  4. Jun 4, 2005 #3


    User Avatar
    Science Advisor
    Gold Member

    Kind of, although strictly speaking, it is 'measuring'.

    Just put a stick of known length inside the tube, and turn it through an angle (so it goes from one chord to another chord, with one point remaining the same). Measure the angle between the two chords, and then get trigg-ing!
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?