Originally Posted by

**earboth** Hello, topsquark,

in general I can understand your solution. But I have one point which I don't understand completely:

The pressure in a (calm, non moving) fluid works always perpendicular to the surface. So the force to the surface depends on the depth of the fluid and the size of the surface.

In the given problem the surface in question is a trapezoid. If I understand your calculatuions right you considered the sidewall to be a rectangle. (But maybe I've misread something)

EB