Which layer of the OSI model is used for establishing,

55      56       52      61       ?       70       34

11      6      7      12      26       ?       205.5

16, 20, 11, 27, ?, 38

3      2       10      ?      17     16

612, 487,?, 396, 388, 387

What value should come in the place of (?) in the following number series?

192, 96, 96, 144, ?, 720

120, 115, 120, 135, 160, ?

(14.073)² + (32.103)² + (43.9653)² + (52.983)² + ? = (102.45)² + (98.007)²

48, 95, 283, 1129, ?, 33841

72, 97, 147, ?, 322, 447