A tree is planted every 4 meters around a circular swimming pool, and a total of 55 trees are planted. What is the circumference of the swimming pool in meters?
在圆形的游泳池边每隔4米种一棵树，共种了55棵，这个游泳池的周长是多少米？
<gadget id="calculator">55 * 4</gadget>
<output>220</output>

<result>220</result>