From Math Images
|Change of Coordinate Systems|
Polar Coordinates are coordinates which locate points by their distance from the origin and their rotation from the positive x-axis. Traditionally, represents distance from the origin and represents rotation in radians from the positive x-axis.
For example, the point is 1 unit from the origin (as can be seen by the Pythagorean Theorem) and is a rotation of from the positive x-axis, so can be represented in polar form by: .