Geometric data type for an arc.

Hi,

Documentation at http://www.postgresql.org/docs/9.1/interactive/datatype-geometric.html#AEN6566 provides an explanation of the PostgreSQL geometric data type for a circle, defined by the two coordinates of a center point and a value that defines the radius of the circle.

What would be the easiest way to store in PostgreSQL an arc or partial circle, defined by the two coordinates of a center point, the two coordinates of the two end points of the arc and the radius of the circle of which the arc is a part?

Regards, Jk.