A rectangular vegetable field has a circumference of 80 meters, and the ratio of its length to width is 7:3. What is the area of the field in square meters?
一块长方形菜地，周长80米，它的长与宽的比是7：3，这块地的面积是多少平方米？
<gadget id="calculator">80 / 2</gadget>
<output>40</output>

<gadget id="calculator">7 + 3</gadget>
<output>10</output>

<gadget id="calculator">7 / 10</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">40 * (7/10)</gadget>
<output>28</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">40 * (3/10)</gadget>
<output>12</output>

<gadget id="calculator">28 * 12</gadget>
<output>336</output>

<result>336</result>