Cut out the largest circle from a piece of paper with a length of 10 decimeters and a width of 8 decimeters. What is the area of this circle in square decimeters?
用一张长10分米、宽8分米的纸剪一个最大的圆，这个圆的面积是多少平方分米．
<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>