A cylinder and a cone with the same base area, their volume ratio is 1:1, the height of the cone is 9 cm, what is the height of the cylinder in cm.
底面积相等的圆柱和圆锥，它们的体积比是1：1，圆锥的高是9厘米，圆柱的高是多少厘米．
<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<result>3</result>