To facilitate the computation of angular deviation of cosmic-ray muons transported through slabs of iron, lead and uranium, we have developed an empirical relation for the angle of deviation with the incident muon energy and the thickness, atomic mass, radiation length and density of the material. This empirical relation can be used for easy calculation of angular deviation of cosmic-ray muons that are proposed for detection of high-Z materials in the presence of materials of low-Z using the muon radiography technique. Our results indicate that uranium and lead can be distinguished from iron while discrimination between lead and uranium is anticipated to face practical difficulties.