There are trees planted around a circular pool, and the distance between every two trees is 3 meters. A total of 48 trees are planted. How many meters does the pool grow in one week?
一个圆形水池的一周栽有树，每两棵树之间的距离是3米，一共栽了48棵树，这个水池一周共长多少米米．
<gadget id="calculator">3 * 48</gadget>
<output>144</output>

<result>144</result>