The height of the cylinder remains the same, the diameter of the bottom surface is enlarged to 4 times of the original, and the volume is enlarged to how many times of the original.
圆柱的高不变，底面直径扩大到原来的4倍，体积扩大到原来的多少倍．
<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<result>16</result>