in study fluid statics text says FrdensityghcenterA but why

in study fluid statics
text says Fr=density×g×h(center)×A
but why they disconsider the p(atm)?
is it wrong Fr=p(atm)×A+density×g×A×h(center)?
i think bottom line does not represent counter p(atm) to offset

Solution

when we are solving these problems in fluid statics we don\'t consider Patm because we are interested in the forces acting to hydrostatic pressure which is rho*g*h . You can also see it as that we consider only gauge pressure and neglect atmospheric pressure because we don\'t take absolute pressure.