If the height of the cylinder remains the same, if the radius of the base is doubled, how many times will its volume be enlarged?
圆柱的高不变，如果底面半径扩大2倍，则它的体积扩大多少倍．
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">4 * 1</gadget>
<output>4</output>

<result>4</result>