There is a lamb in the field, tied to a stake with a 3-meter-long rope, what is the maximum grazing area of the lamb in square meters?
田野里有一只小羊，用长为3米的绳子栓在木桩上，小羊的最大吃草面积是多少平方米？
<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

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

<result>28.26</result>