With the primitive oval selected on the Stage, you can
use the controls found in the Property inspector to further modify
the shape, or specify fill and stroke colors.

Properties for an oval primitive
The Property inspector controls specific to the Primitive
Oval tool are:
Start angle and End angle Let you specify
the angle of the start and end points of the oval. Using these controls,
you can easily modify the shape of ovals and circles into pie slices,
half circles, and other creative shapes.
Inner radius Lets
you specify an inner radius (or oval) within the oval. You can either
enter a numerical value for the inner radius in the box, or click
the slider and interactively adjust the size of the inner radius.
The numerical values you can enter for the inner radius range from
0 to 99, and represent the percentage of the oval’s fill that is
removed.
Close path Lets you specify whether the path
(or paths, if you are specifying an inner radius) of the oval is
closed. If you specify an open path, no fill is applied to the resulting
shape, only the stroke is drawn. Close path is selected by default.
Reset Resets
all of the Oval Primitive tool’s controls, and returns the primitive oval
shape drawn on the stage to its initial size and shape.