Master Li plans to make a cuboid ventilation pipe out of iron sheets. The length of the pipe is 10 meters, and the mouth of the pipe is a square with a side length of 4 decimeters. How many square decimeters of iron sheet should be used to make this ventilation pipe? (Welding area is ignored)
李师傅计划用铁皮做一个长方体的通风管．管长10米，管口是一个边长4分米的正方形，做这个通风管至少要用铁皮多少平方分米？(焊接处面积忽略不计)
<gadget id="calculator">4 * 4 * 10 * 10</gadget>
<output>1_600</output>

<result>1_600</result>