Make 10 sections of cylindrical ventilation pipes with tin, each section is 80 centimeters long, and the radius of the bottom circle is 10 centimeters, how many square decimeters of tin is needed at least?
用白铁皮制作圆柱形通风管道10节，每节长80厘米，底面圆的半径是10厘米，这样至少需要白铁皮多少平方分米？
<gadget id="calculator">2 * 3.14 * 10 * 80</gadget>
<output>5_024</output>

<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">5_024 * (1/10)</gadget>
<output>2_512/5 = around 502.4</output>

<result>2_512/5 = around 502.4</result>