Bridgette has drawn a representation of a sphere with a radius of 3
units, using the graphs of a circle and an ellipse, as shown in the pic-
ture below on the left.
She needs to determine the equations of the graphs that will generate
the representation of the 3D sphere, as shown in the picture below on
the right.
What are possible equations of the circle and ellipse that Bridgette can
use to create her 3D drawing?