To calculate the hydraulic force acting on a plate using four cylinders, knowing the diameter of the cylinders is essential, but additional information is needed. Specifically, the total load on the plate and how that load is distributed are crucial for determining how much force each cylinder will carry. If the load is evenly distributed, each cylinder will support a quarter of the total load. Additionally, understanding whether the hydraulic ram is pushing or pulling will affect the calculations, as it determines the pressure on the bore side of the ram. Ultimately, knowing the hydraulic pressure and the cylinder's cross-sectional area allows for the calculation of the force exerted by the hydraulic system.