The perimeter of a square camphor forest is 1200 meters. If the side length is reduced by 100 meters, how many hectares will the area be reduced?
一块正方形樟树林的周长是1200米，若边长减少100米，则面积减少多少公顷？
<gadget id="calculator">1_200 / 4</gadget>
<output>300</output>

<gadget id="calculator">300 * 300</gadget>
<output>90_000</output>

<gadget id="calculator">300 - 100</gadget>
<output>200</output>

<gadget id="calculator">200 * 200</gadget>
<output>40_000</output>

<gadget id="calculator">90_000 - 40_000</gadget>
<output>50_000</output>

<gadget id="calculator">50_000 / 10_000</gadget>
<output>5</output>

<result>5</result>