This sample shows the required steps to approximate data with an Ellipse.
Select data series on left panel [Points].
Select menu item
The 'Approximation line' Wizard appears.
On step (3 of 6) select checkbox item 'Ellipse' checked.
New graph appears. See how curve fit conforms your data.
It uses nonlinear regression (Simplex method) to minimize the distance from 2D (X,Y) data points to an ellipse.
On step 5 select line color and click
Findgraph uses the parametric way to present ellipse.