The nozzle used for watering the park green space can spray water at a distance of 5 meters, and the nozzle rotates once. What is the maximum spraying area in square meters?
公园绿地里浇水用的喷头，最远能喷水5米，喷头旋转一周，最大的喷水面积是多少平方米．
<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<result>78.5</result>