  We define evaluation forms associated to objects in a module subcategory of
Ext-symmetry generated by finitely many simple modules over a path algebra with
relations and prove a multiplication formula for the product of two evaluation
forms. It is analogous to a multiplication formula for the product of two
evaluation forms associated to modules over a preprojective algebra given by
Geiss, Leclerc and Schr\"oer in \cite{GLS2006}.
