The standard equation of an ellipse is[br][size=100][math]\frac{\left(x-h\right)^2}{a^2}+\frac{\left(y-k\right)^2}{b^2}=1[/math][br][/size][br]You can see this is more involved than the circle formula, but it is related.[br][br]Ellipse Rules:[br]An ellipse is "horizontal" if the value of "a" is larger[br]An ellipse is "vertical" if the value of "b" is larger[br][br]Use the app to see how the formula changes[br]