 These can be found by transposing and substituting the last two equations above;

The unbalanced pi pad can be converted to a balanced O pad by putting one half of Rz in each side of a balanced line.The simple four element O pad attenuates the differential mode signal but does little to attenuate any common mode signal.To insure attenuation of the common mode signal also, a split O pad can be created by splitting and grounding Rx and Ry.