If a cone with a height of 6dm is cut in half along the height and the surface area is increased by 120dm**2, what is the volume of the cone? (Expressed by a formula containing π).
把一个高6dm的圆锥，沿高切成两半，表面积增加120dm**2，原来这个圆锥的体积是多少．(用含π的式子表示)．
<result>200</result>