In a rectangle with a length of 6 meters and a width of 4 meters, cut out the largest circle, what is the area of the circle in square meters
在一个长6米，宽4米的长方形内，剪下一个最大的圆，圆的面积是多少平方米
<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>