Most engineering structures and equipment vibrate, and the dynamic behaviour of these structures must often be taken into account during design. Because of this, the study of vibration, which examines the vibratory behaviour of bodies, is becoming increasingly important in various engineering applications, including nuclear reactor technology and aviation. A minimal amount of research has been done on visco-elastic triangular plates compared to the fields of rectangular, square, and circular plates. In this work, the free vibration of a visco-elastic triangular plate with a simply supported boundary condition and parabolically increasing thickness is studied about taper constants. The Cartesian product of parabolic variations is considered the two-dimensional thickness variation. The frequency equation is derived using the Rayleigh-Ritz technique. The findings are displayed graphically.