I was looking at the equation of a circle in polar coordinates on wikipedia,(adsbygoogle = window.adsbygoogle || []).push({});

http://en.wikipedia.org/wiki/Polar_coordinate_system

and I understand that a is the radius of the circle, and that (r0, phi) is the center of the circle. But I don't see what the r and theta refer to :(.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Equation of a circle / polar coordinates

**Physics Forums | Science Articles, Homework Help, Discussion**