How can you determine if a circuit is a series circuit or parallel circuit

Aforce of 6600 n is exerted on a piston that has an area of 0.010 [tex]m^{2}[/tex]. what area is rewired for a second piston to exert a force of 9900 n? use [tex]\frac{f_{1} }{a_{1} } = \frac{f_{2} }{a_{2} }[/tex]a. 0.0015 [tex]m^{2}[/tex]b. 66 [tex]m^{2}[/tex]c. 150 [tex]m^{2}[/tex]d. 0.006 [tex]m^{2}[/tex]