A circular or square vegetable garden is surrounded by a 12.56-meter-long fence. Which shape of the vegetable garden occupies the largest area? How big is it?
用12.56米长篱笆围成圆形或正方形的菜园，哪种形状的菜园占地面积大？大多少？
<gadget id="calculator">12.56 / 3.14 / 2</gadget>
<output>2</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<gadget id="calculator">4 / 4</gadget>
<output>1</output>

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

<gadget id="calculator">3.14 * 3.14</gadget>
<output>9.8596</output>

<gadget id="calculator">12.56 - 9.8596</gadget>
<output>2.7004</output>

<result>2.7004</result>