A farm plans to excavate and level the wasteland around a rectangular piece of land with a length of 400 meters and a width of 200 meters, so that the land becomes a square land with a side length of 500 meters. Find out how many hectares the area of the square land has increased from the original ?
某农场计划将一块长400米，宽200米的长方形土地周围的荒地开挖平整，使这块土地变成一块边长500米的正方形土地，求这块正方形土地的面积比原来增加了多少公顷？
<gadget id="calculator">500 * 500</gadget>
<output>250_000</output>

<gadget id="calculator">400 * 200</gadget>
<output>80_000</output>

<gadget id="calculator">250_000 - 80_000</gadget>
<output>170_000</output>

<gadget id="calculator">170_000 / 10_000</gadget>
<output>17</output>

<result>17</result>