A rectangular vegetable field has an area of 28 square meters and a length of 7 meters. A bamboo fence is placed around the vegetable field. What is the length of the fence in meters?
一块长方形菜地，面积是28平方米，长7米，沿菜地的四周围上一个竹篱笆，篱笆的长是多少米．
<gadget id="calculator">28 / 7</gadget>
<output>4</output>

<gadget id="calculator">4 + 7</gadget>
<output>11</output>

<gadget id="calculator">11 * 2</gadget>
<output>22</output>

<result>22</result>