The sides of the cylindrical carton can be made by rolling up the cuboid paper, and then a cylindrical carton can be made by adding two bottom surfaces. Then two circular pieces of paper with a radius of 3 cm can be combined with how many medium-rectangular pieces of paper to make a cylindrical carton.
把长方体的纸片卷起来就可以做圆柱体纸盒的侧面，再装上两个底面就可以做成一个圆柱体纸盒．那么两个半径是3cm的圆形纸片刚好可以和多少中长方形纸片做成一个圆柱体纸盒．
<gadget id="calculator">3.14 * 3 * 2</gadget>
<output>18.84</output>

<result>18.84</result>