The initial force applied is multiplied in the process by means of increasing the area of application. Therefore, the multiplication is derived by increasing the sizes of the pistons at either end.
In braking systems, the piston at the end of application of force, driving the fluid is smaller than the pistons at the brake pads. Therefore the force is multiplied many times, helping to brake easily and more efficiently.
Another important characteristic of hydraulics is that the pipes having the fluid can be of any size, length or shape which allows the lines to be fed almost anywhere. They can also be split to let the master cylinder to operate two or more slave cylinders in case of a need.