A cone of slant height r and apex O was constructed using a metal lamina in the shape of the sector shown in the figure. The centre and the radius of the sector are O and r respectively.n pieces of ice in the shape of spheres of radius a are placed in this cone. (The cone is held inverted). If the cone is filled completely with water when all the ice melts show that 125ncubic a(a3) = 9 cubic r​