1. The problem statement, all variables and given/known data

An oil filled system is shown in the figure below. The density of the oil is
.

In the figure(Figure 1)how much force does the fluid exert on the end of the cylinder at A?

2. Relevant equations

3. The attempt at a solution

Solved for P_{oil} using P = P_{o} + F/A = 1.79 X 10^{5}. Simple enough.

Since pressure is the same across any level, we first have to first figure out the distance from P_{o} to the top of A. This is where I am stuck. I feel like its something very simple but I just dont see it!

Spoiler

The distance is 70cm. We did this one in class, but I still dont see it.