There is a square vegetable garden with a side length of 10 meters. If you want to build a fence around the vegetable garden, how many meters should the fence be at least?
有一个正方形菜园，边长是10米，要想紧紧围绕菜园周边建上栅栏，那么栅栏圈起来至少多少米
<gadget id="calculator">10 * 4</gadget>
<output>40</output>

<result>40</result>