cuboid ventilation pipe, each 6 meters long, has a cross-section of a square with side length 50 cm. How much iron sheet does it take to make a vent pipe like this?
一种长方体的通风管，每根长6米，横截面是边长50厘米的正方形．做一根这样的通风管需要多少铁皮？
<gadget id="calculator">6 * 100</gadget>
<output>600</output>

<gadget id="calculator">50 * 4 * 600</gadget>
<output>120_000</output>

<result>120_000</result>