The ratio of length to width of a rectangular lawn is 8:5, and its circumference is 1040 meters. What is the area of this lawn in hectares?
一块长方形草坪长与宽的比是8：5，周长是1040米，这块草坪的面积是多少公顷？
<gadget id="calculator">1_040 / 2</gadget>
<output>520</output>

<gadget id="calculator">8 + 5</gadget>
<output>13</output>

<gadget id="calculator">5 / 13</gadget>
<output>5/13 = around 0.384615</output>

<gadget id="calculator">8 / 13</gadget>
<output>8/13 = around 0.615385</output>

<gadget id="calculator">(8/13) / 10_000</gadget>
<output>1/16_250 = around 0.000062</output>

<gadget id="calculator">520 * (5/13) * 520 * (1/16_250)</gadget>
<output>32/5 = around 6.4</output>

<result>32/5 = around 6.4</result>