If the base radius and height of a cylinder are doubled, how many times will its lateral area be enlarged?
一个圆柱的底面半径和高都扩大到原来的2倍，它的侧面积扩大到原来的多少倍．
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<result>4</result>