Wolfram Research
Wolfram Math World: Polar Coordinates
This math link contains a plethora of information on Polar coordinates. The site begins with a diagram illustrating the measurements used when working with polar coordinates then goes into detail on specifics of using this coordinate...
Wolfram Research
Wolfram Math World: Area
Definitions and formulas for the computation of surface areas of triangles, rectangles, and any regular polygon. Helpful links to related pages.