The difference between the length and width of the rectangular playground is 40 meters. A student ran 3 laps along the edge of the playground, a total of 1200 meters. What is the area of the playground in square meters?
长方形操场的长与宽相差40米，某同学沿操场边跑了3圈，共1200米．这个操场的面积是多少平方米．
<gadget id="calculator">1_200 / 3 / 2</gadget>
<output>200</output>

<gadget id="calculator">200 - 40</gadget>
<output>160</output>

<gadget id="calculator">160 / 2</gadget>
<output>80</output>

<gadget id="calculator">80 + 40</gadget>
<output>120</output>

<gadget id="calculator">80 * 120</gadget>
<output>9_600</output>

<result>9_600</result>