Choose the Ellipse By 3 Points command 
.
Click where you want the primary axis to begin (A).
Click where you want the primary axis to end (B). This defines the length of the primary axis and the rotation angle.
Click a location on one side of the primary axis (C). This defines the secondary axis.
Tip:
The primary axis can be shorter than the secondary axis.
Instead of clicking to define the primary and secondary axes of an ellipse, you can type values on the Ellipse command bar. You can also use a combination of graphic and command bar input.
IntelliSketch places relationship handles.
You can use the options on the command bar and the commands on the shortcut menu to edit an ellipse.