Yushan Forest Farm has a square pine forest with a circumference of 2800 meters. How many hectares does this pine forest cover?
虞山林场有一块正方形的松树林，周长是2800米，这个松树林占地多少公顷？
<gadget id="calculator">2_800 / 4</gadget>
<output>700</output>

<gadget id="calculator">2_800 / 4 / 10_000</gadget>
<output>7/100 = around 0.07</output>

<gadget id="calculator">700 * (7/100)</gadget>
<output>49</output>

<result>49</result>