On a plan with a scale of 1:20,000, the perimeter of a rectangular field is 24 cm, and the ratio of length to width is 5:3. What is the actual area of the test field in hectares?
在一张比例尺是1：20000的平面图上，一块长方形的地的周长是24厘米，长和宽的比是5：3，这块试验田实际面积是多少公顷．
<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<gadget id="calculator">5 + 3</gadget>
<output>8</output>

<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">1 / 20_000</gadget>
<output>1/20_000 = around 0.00005</output>

<gadget id="calculator">(5/8) / (1/20_000) / 100</gadget>
<output>125</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(3/8) / (1/20_000) / 100 / 10_000</gadget>
<output>3/400 = around 0.0075</output>

<gadget id="calculator">12 * 125 * 12 * (3/400)</gadget>
<output>135</output>

<result>135</result>