Other
Calculus Animations With Mathcad: Polar Curves
Contains an animation that will show you how the graphs of a number of polar equations are graphed. (Page may take some time to load completely.)
University of Georgia
University of Georgia: Polar Equations
This site discusses how to graph a polar equation and gives several pretty graphed examples.
Curated OER
Parametric Unit Circle
This site provides definitions for different parts of a circle, pictures to more clearly represent formulas involving circles. Some of the formulas discussed include: area of a circle, area of a sector of a cirles, circumference, length...