Calculating Gravitational Potential Energy of a Fluid Above a Reference Line

[cwrn]

I got a quick question regarding the potential energy of a fluid (see picture). If I want to express the potential energy of a fluid (with a given volume) above the reference line x, using nothing but the given variables/constants, would this be the correct way to do so?

picture

 

[paisiello2]

Without doing any calculus, the gravitational potential energy of a mass from a distance from x to it's center of mass= h is:
U = mgh
= (ρAs)(g)(s/2)
= 1/2ρAgs²
= 1/2ρAg(y-h)²

Which gives the same answer.