There is a section of steel with a length of 2 meters and a radius of 0.4 meters at the bottom. It is necessary to forge it into a rectangular part blank with a length of 0.8 meters and a width of 0.4 meters. It is assumed that the loss of steel during the forging process can be ignored. Not counting, find the height of the blank of the rectangular part.
有一段长为先有一段长为2米，底面半径为0.4米的圆柱体钢材，要把它锻造成一个长0.8米，宽为0.4米的长方形零件毛坯，假设锻造过程中钢材的损耗可忽略不计，求长方形零件毛坯的高．
<gadget id="calculator">0.4 ** 2</gadget>
<output>0.16</output>

<gadget id="calculator">0.8 * 0.4</gadget>
<output>0.32</output>

<gadget id="calculator">2 / 0.32</gadget>
<output>6.25</output>

<gadget id="calculator">3.14 * 0.16 * 6.25</gadget>
<output>3.14</output>

<result>3.14</result>