square steel billet with a side length of 2 decimeters is forged into a rectangular parallelepiped steel with a height and a width of 4 centimeters. What is the length of the forged cuboid steel? (Solution by equation and arithmetic method)
把一块棱长是2分米的正方体钢坯，锻造成高和宽都是4厘米的长方体钢材．锻造成的长方体钢材的长是多少？(用方程和算术法两种方法解答)
<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<gadget id="calculator">20 / 16</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">20 * 20 * (5/4)</gadget>
<output>500</output>

<result>500</result>