On the 1:500 floor plan, the length of a rectangular playground is 24 cm and the width is 18 cm. What is the actual perimeter of this rectangular playground in kilometers?
在1：500的平面图上，量得一块长方形操场的长是24厘米，宽是18厘米，这块长方形操场的实际周长是多少千米？
<gadget id="calculator">1 / 500</gadget>
<output>1/500 = around 0.002</output>

<gadget id="calculator">24 / (1/500) / 1_000_000</gadget>
<output>3/250 = around 0.012</output>

<gadget id="calculator">90_000 / 10_000_000</gadget>
<output>9/1_000 = around 0.009</output>

<gadget id="calculator">(3/250) + (9/1_000)</gadget>
<output>21/1_000 = around 0.021</output>

<gadget id="calculator">(21/1_000) * 2</gadget>
<output>21/500 = around 0.042</output>

<result>21/500 = around 0.042</result>