cuboid ventilation pipe is 4 meters long, and the cross section is a square with a side length of 3 decimeters. How many square meters of iron sheets are needed to make 8 such ventilation pipes?
一种长方体通风管长4米，横截面是边长3分米的正方形，做8节这样的通风管，至少需要多少平方米的铁皮？
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(3/10) * 4 * 4 * 8</gadget>
<output>192/5 = around 38.4</output>

<result>192/5 = around 38.4</result>