The rectangular swimming pool has an area of 800 square meters and a length of 40 meters. Find the perimeter of the swimming pool?
长方形游泳池面积为800平方米，长为40米．求游泳池的周长？
<gadget id="calculator">800 / 40</gadget>
<output>20</output>

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

<gadget id="calculator">60 * 2</gadget>
<output>120</output>

<result>120</result>