An analytic solution for the acoustic radiation from a rib‐reinforced infinite elastic plate which is excited by a point force located on the rib was obtained. The solution exhibits a new coincidence angle, where the radiated pressure peaks, which depends on the relative stiffness and mass of the attached beam. An expression for the radiated power was also obtained which shows the general reduction of radiated power explicitly as a function of the mass and stiffness of the attached beam. Approximate formulas for the complex interaction between the beam and the plate were developed for frequencies above and below the coincidence frequency. Approximate expressions for the radiated power were obtained from simplified physical models.