How will you find the center of mass of a triangular lamina?
Let the lamina (∆LMN) is subdivided into narrow strips each parallel to the base (MN)
By symmetry, each and every strip has its centre of mass at its mid-point. On joining the mid-points of all strips we get the median LP. Therefore the centre of mass of the triangle as a whole lie on the median LP. Similarly, we can say that it lies on the median MQ and NR. It means that centre of mass lies on the point of concurrence of the median, which is on the centroid G of the triangle.