3 ms·

12”/14”/16” ~> 30/35/41 cm. Also note that area is proportional to the square of the diameter.

• leetrout 5y ago
  Area of a circle is Pizza Given a radius of z: Pi•z•z=a
  • jbverschoor 5y ago
    Gold
  • hawk_ 5y ago
    brilliant! source? or did you just make it up?
    • leetrout 5y ago
      No — I think I read it on here some while back. So simple and easy to remember; I love it and love repeating it!