2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/170578We derive the spectrum of the Laplace-Beltrami operator on the quotient orbifold of the non hyperbolic triangle groups.accepted in the Journal of the Australian Mathematical SocietySpectral Theory14L35, 47A75, 20C99The spectra of the spherical and euclidean triangle groupstext