To make a kind of ventilation pipe, each length is 1.5 meters, and the mouth of the pipe is a square with a side length of 5 decimeters. How many square meters of iron sheet are needed to make 100 such ventilation pipes?
做一种通风管，每根长1.5米，管口是边长5分米的正方形，做100根这样的通风管至少需要铁皮多少平方米？
<gadget id="calculator">5 / 10</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) * 4 * 1.5 * 100</gadget>
<output>300</output>

<result>300</result>