Create an elliptical shape from a center point, a major axis, and a minor axis. The first click sets the center point, the second click sets the direction and length of the first axis, and the third point can be any point on the ellipse.
Access
Ribbon:
Sketch tab
Draw pane
Ellipse
You can trim and extend ellipses in the same manner as any other curve.
Note: With the Offset command, you can create a curve that is either an ellipse or a spline, depending on the selection point. When the axis is visible, the offset is an ellipse; if the axis is not visible, the offset is a spline.