There is a circular lawn with a circumference of 62.8 meters. It is planned to install an automatic rotary sprinkler device for irrigation. How many meters of the device is suitable for installation.
有一个周长62.8米的圆形草坪，准备为它安装自动旋转喷灌装置进行喷灌，装射程为多少米的装置合适．
<gadget id="calculator">62.8 / 3.14 / 2</gadget>
<output>10</output>

<result>10</result>