If the height of a cuboid remains the same, the length and width are increased by 3 times, and the volume is increased by how many times.
一个长方体的高不变，长和宽都扩大3倍，体积扩大多少倍．
<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<result>9</result>