If a sheep is tied to a stake with a 3-meter-long rope, what is the maximum area that the sheep grazes in square meters?
把一只羊用3米长的绳子系在一根木桩上，这只羊吃草的面积最多是多少平方米？
<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<result>28.26</result>