If the height of a cylinder remains the same and the radius of the base is reduced by 3 times, its volume will be reduced by how many times.
一个圆柱的高不变，底面半径缩小3倍，它的体积缩小多少倍．
<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<result>9</result>