Cut the largest circle on a piece of rectangular paper with a length of 10dm and a width of 8dm. What is the area of this circle in dm**2.
在一张长10dm，宽8dm的长方形纸上剪一个最大的圆，这个圆的面积是多少dm**2．
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16</gadget>
<output>50.24</output>

<result>50.24</result>