A cylinder and a cone have the same volume and the same base area. The height of the cylinder is 21 decimeters. What is the height of the cone in decimeters?
一个圆柱与圆锥体积相等，底面积也相等，圆柱的高为21分米，圆锥体的高是多少分米．
<gadget id="calculator">21 * 3</gadget>
<output>63</output>

<result>63</result>