Take a piece of rectangular paper with a length of 18 cm and a width of 12 cm, roll it into a cylindrical paper tube, and then match it with a suitable bottom to form a container without a lid. What is the maximum volume of this container? (negligible at joints, π≈3)
用一张长18厘米、宽12厘米的长方形纸，卷成一个圆柱形纸筒，再给它配一个合适的底面就成了一个无盖容器，这个容器的最大容积是多少？(接头处忽略不计，π≈3)
<gadget id="calculator">18 / 3 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3 * 9 * 12</gadget>
<output>324</output>

<result>324</result>