In Fig. `ABC` is a uniform triangular lamina. It may be subdivided into thin strips, each parallel to the base `BC` as shown,
By symmetry, each strip has its centre of mass at its geometrical centre. If these points are joined, we get the medium `AK`. similarly, we can argue that centre of mass lies on median `BL` and also on median `CM`. it means the centre of mass of unifrom triangular lamina lies at the point of intersection of the three median, i.e., on the centroid `G` of the triangle.
