It is 28 centimeters to make a square nozzle circumference, and there are 10 ventilation pipes with a length of 2 meters, how many square meters of iron sheets are needed at least?
要做一个正方形管口周长是28厘米，长2米的通气管子10根，至少需要铁皮多少平方米？
<gadget id="calculator">28 / 100</gadget>
<output>7/25 = around 0.28</output>

<gadget id="calculator">(7/25) * 2 * 10</gadget>
<output>28/5 = around 5.6</output>

<result>28/5 = around 5.6</result>