Divide a circle into equal parts and assemble it into an approximate rectangle. It is known that the perimeter of the rectangle is 16.56 centimeters. What is the area of the original circle in square centimeters?
把一个圆形等分后拼成近似的长方形，已知长方形的周长是16.56厘米，那么原来这个圆形的面积是多少平方厘米．
<gadget id="calculator">16.56 / 8.28</gadget>
<output>2</output>

<gadget id="calculator">3.14 * 2 * 2</gadget>
<output>12.56</output>

<result>12.56</result>