There is a circular lawn with a circumference of 113.04m. It is planned to install an automatic rotary sprinkler device for irrigation. There are three devices with a range of 20m, 18m and 15m. Which one do you think is more suitable? Where is it installed?
有一个周长为113.04m的圆形草坪，准备安装自动旋转喷灌装置进行喷灌，现有射程为20m、18m、15m的三种装置，你认为应选哪种比较合适？安装在什么地方？
<gadget id="calculator">113.04 / 3.14 / 2</gadget>
<output>18</output>

<result>18</result>