Do you know the general formulas of each? If you do, then there should be no trouble. Parabolas are very easy to see, but the difference between circles and ellipses are elusive. Think of a circle as an ellipse where the major and minor axis lengths are the same. That way, justturn the equation into an ellipse and if they are the same, it is a circle, if not it is an ellipse. From the sheet, you are correct for all problems.