Using a square paper with a side length of 2 decimeters, cut a circle with the largest possible area. What is the area of this circle in square decimeters?
用一个边长是2分米的正方形纸，剪一个面积尽可能大的圆，这个圆的面积是多少平方分米．
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">1 ** 2</gadget>
<output>1</output>

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

<result>3.14</result>