The side length of a piece of square paper is 2 decimeters, cut it into a largest circle, what is the area of the circle in square decimeters?
一张正方形纸的边长是2分米，把它剪成一个最大的圆，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>