Cut out the largest circle on a rectangular steel plate with a width of 4 decimeters and a length of 6 decimeters. What is the area of this circle in square decimeters?
在一个宽为4分米、长为6分米的长方形钢板上，剪出一个最大的圆，这个圆的面积是多少平方分米．
<gadget id="calculator">4 / 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>

<result>12.56</result>