piece of cylindrical steel with a base diameter of 6 cm and a height of 4 cm is melted and cast into a cone with the same area as the original base. What is the height of the cone in cm?
把一段底面直径是6厘米，高是4厘米的圆柱形钢材，熔铸成一个和原来底面积相等的圆锥，圆锥的高是多少厘米．
<result>12</result>