Fluids 2

A 6-in.-diameter piston is located within a cylinder that is connected to a inclined-tube manometer whose diameter is $\frac{1}{2}$ inch as shown
. The fluid in the cylinder and the manometer is oil with (specific weight  "59 $\frac{lb}{ft^{3}}$ )
.When a weight, "W" is placed on the top of the cylinder, the fluid level in the manometer tube rises from
point (1) to (2). Find the weight W ( in lb ) Assuming that the change in position of the piston is negligible.
.