In this third paper of the series, which started with Bailey et al. ͓J. Chem. Phys. 129, 184507 ͑2008͒; ibid. 129, 184508 ͑2008͔͒, we continue the development of the theoretical understanding of strongly correlating liquids-those whose instantaneous potential energy and virial are more than 90% correlated in their thermal equilibrium fluctuations at constant volume. The existence of such liquids was detailed in previous work, which identified them, based on computer simulations, as a large class of liquids, including van der Waals liquids but not, e.g., hydrogen-bonded liquids. We here discuss the following: ͑1͒ the scaling properties of inverse power-law and extended inverse power-law potentials ͑the latter includes a linear term that "hides" the approximate scale invariance͒; ͑2͒ results from computer simulations of molecular models concerning out-of-equilibrium conditions; ͑3͒ ensemble dependence of the virial/potential-energy correlation coefficient; ͑4͒ connection to the Grüneisen parameter; and ͑5͒ interpretation of strong correlations in terms of the energy-bond formalism.