A circular pool has a circumference of 180 meters. If a poplar is planted every 4 meters along the circumference, how many poplars should be planted in total?
一个圆形水池，周长180米，如果沿着周围每隔4米栽一棵杨树，一共需要栽杨树多少棵．
<gadget id="calculator">180 / 4</gadget>
<output>45</output>

<result>45</result>