Which equation represents the pythagorean theorem, which can be used to find the magnitude of resultant vectors?

r = a + b

r = a x b

r2 = a2 x b2

r2 = a2 + b2

The pressure proportional to the area a- inversely b- directly c- increase d-decrease

The sound level near a noisy air conditioner is 70 db. if two such units operate side by side, the sound level near the, would bea. 70dbb. 73 dbc. 105 dbd 140 db

Refrigerant-134a flows through a carnot heat pump cycle at 0.5 kg/s. it is known that the maximum absolute temperature in the cycle is 1.1 times the minimum absolute temperature, and the net power input to the cycle is 2.5 kw. if the refrigerant changes from a saturated vapor to a saturated liquid during the heat rejection process, determine the maximum magnitude of the enthalpy of vaporization for this process in kj/kg (with 3 significant figures).