If the perimeter of a rectangular swimming pool is 120 meters and the length is 40 meters, what is the area of the rectangular swimming pool in square meters?
一个长方形游泳池的周长是120米，长是40米，则这个长方形游泳池的面积是多少平方米？
<gadget id="calculator">120 / 2</gadget>
<output>60</output>

<gadget id="calculator">60 - 40</gadget>
<output>20</output>

<gadget id="calculator">40 * 20</gadget>
<output>800</output>

<result>800</result>