A square vegetable field is surrounded by a wall on one side and a fence on the other three sides. The length of the fence is 27 meters. What is the circumference of this vegetable field in meters?
一块正方形菜地，一面靠墙，其他三面围篱芭，篱笆长是27米，这块菜地的周长是多少米．
<gadget id="calculator">27 / 3</gadget>
<output>9</output>

<gadget id="calculator">9 * 4</gadget>
<output>36</output>

<result>36</result>