Polar graphs provide graphs of a data with respect to a polar coordinate system rather than a cartesian or rectangular coordinate system. A polar graph plots a point at some radial distance along a ray that creates a given angle with the positive X axis. For polar graphs, the angular measurement and radial components correspond to the X and Y coordinates in a line graph, respectively.
You can manipulate polar graphs just as you would line graphs, except you cannot display a label on the Y axis.