A cylinder of water is filled with water, the distance between the water surface and the mouth of the cylinder is 10 cm, and the radius of the base of the cylinder is 5 cm. Put a cone with the same base and height as the cylinder into the water cup, the water surface just reaches the mouth of the cup, find the height of the cone.
一个圆柱体水杯中装有水，水面距圆柱体的杯口的距离为10厘米，这个圆柱的底面半径是5厘米．把一个与圆柱体等底等高的圆锥放入水杯中，水面刚好到杯口，求这个圆锥体的高．
<gadget id="calculator">3 / 1</gadget>
<output>3</output>

<gadget id="calculator">10 * 3</gadget>
<output>30</output>

<result>30</result>