Ellipse Construction, Continued
Determining
foci
To determine the foci of an ellipse, strike arcs with a radius equal to half the
major axis and with the center at the end of the minor axis.
Another method
is to draw a semicircle with the diameter equal to the major axis of the
ellipse. Then draw GH parallel to the major axis. Draw GE and HF parallel
to the minor axis.
Figure 2-46 show how to determine foci.
Figure 2-46.—Determining foci.
Continued on next page
2-46
