Divide a circle into several equal parts and form an approximate rectangle. The length of this approximate rectangle is 12.56 decimeters. What is the area of this circle in square decimeters?
把一个圆平均分成若干份后，拼成一个近似的长方形，这个近似长方形的长是12.56分米．这个圆的面积是多少平方分米？
<gadget id="calculator">12.56 / 3.14</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>