There is a large circular lawn with a circumference of 125.6 meters, and an automatic rotary sprinkler irrigation device is now ready to be installed. Now there are 4 kinds of devices with a range of 10 meters, 15 meters, 20 meters and 25 meters. Which one do you think is more suitable? Where is the most appropriate place to install?
有一个圆形的大草坪，周长是125.6米，现在准备安装一个自动旋转喷灌装置．现在有射程10米、15米、20米、25米的4种装置，你认为选哪种比较合适？安装在什么位置最恰当？
<gadget id="calculator">125.6 / 3.14 / 2</gadget>
<output>20</output>

<result>20</result>