The angular dependence of the magnetic dichroism in core-level photoemission using linearly polarized light has been measured. The intensity asymmetry of Co 3p spectra of Co/Cu(100) ultrathin films upon magnetization reversal has been determined in normal emission, under variation of both polar and azimuthal angles of light incidence. The results are compared to general theoretical predictions of angle-resolved X-ray magnetic dichroism for photoemission along directions of high symmetry. Good agreement between the experimental results and the predicted angular dependences is found, thus confirming that interference terms in the dipole matrix elements are responsible for the angle-resolved magnetic dichroism.