A piece of iron chimney is 1.5 meters long and 0.2 meters in diameter. To make 500 sections of such chimneys, how many square meters of iron sheet should be used at least? (π takes 3.1)
一节铁皮烟囱长1.5米，直径是0.2米，做这样的烟囱500节，至少要用铁皮多少平方米？(π取3.1)
<gadget id="calculator">3.1 * 0.2 * 1.5</gadget>
<output>0.93</output>

<gadget id="calculator">0.93 * 500</gadget>
<output>465</output>

<result>465</result>