Abstract: Oval is a very common graphics in life, however it is not clearly defined in mathematics
and engineering. It is still in the stage of circle and ellipse for studying the oval. In this paper,
according to the descriptive definition of oval, a kind of cubic and standard equation is firstly given
by mathematical analysis and derivation. A determining method is proposed whether a cubic equation
is an oval equation or not, and the approach is given about how to calculate long, short and symmetry
radius. To some extension, the proposed method can solve the problem about the oval without a
mathematical expression. By analyzing the real images of an egg, the real parameter values of long,
short and symmetry radius are obtained. These values are input to the oval equation, the graphics is
drawn using computer program. Compared with the real images of eggs, the highly consistent results
can be achieved.

Key words: oval, oval equation, oval center, long radius, short radius, symmetric radius