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

Pi=90 how do you find out

  1. Aug 22, 2008 #1
    cos pi= -1
    using the 360 circle ir those quadrants
    i forgot what it was, link
  2. jcsd
  3. Aug 23, 2008 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    First of all "pi" is NOT "90". Get that out of your head! Nor does "pi radians" correspond to "90 degrees" if that was what you meant. "pi radians" corresponds to "180 degrees", half a circle. The crucial thing you need to remember is that a full circle is 360 degrees, 2pi radians. Perhaps it would help to remember that a circle has circumference pi*d= 2pi *r. That's where the "2pi" comes from.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?