The tiger mountain in the zoo is circular, and its radius is 20 meters. How many square meters does the tiger mountain cover?
动物园的虎山是圆形的，它的半径是20米，虎山的占地面积是多少平方米？
<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

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

<result>1_256</result>