If the diameter of the base of the cylinder is doubled and the height remains the same, the volume of the cylinder will be increased by as many times as possible.
圆柱体的底面直径扩大2倍，高不变，圆柱体积就扩大多少倍．
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<result>4</result>