If the perimeter of a rectangle is 36 decimeters and the width is 4/5 of the length, what is the area of the rectangle in square decimeters?
一个长方形的周长36分米，宽是长的(4/5)，长方形的面积是多少平方分米．
<gadget id="calculator">36 / 2</gadget>
<output>18</output>

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