There is an automatic rotary sprinkler on the school lawn with a range of 20 meters. How many square meters of grass can this sprinkler cover at most?
学校草地上有一个自动旋转洒水器，射程是20米，这个洒水器最多可以淋到多少平方米的草地？
<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

<gadget id="calculator">3.14 * 400</gadget>
<output>1_256</output>

<result>1_256</result>