A rectangular vegetable field is surrounded by a 36-meter-long fence, and the ratio of length to width is required to be 5:4. What is the area of this vegetable field in square meters?
用36米长的篱笆围成一个长方形菜地，要求长与宽的比是5：4，这块菜地的面积是多少平方米？
<gadget id="calculator">36 / 2</gadget>
<output>18</output>

<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">18 * (5/9)</gadget>
<output>10</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">18 * (4/9)</gadget>
<output>8</output>

<gadget id="calculator">10 * 8</gadget>
<output>80</output>

<result>80</result>