Divide a circle into even-numbered equal parts, cut them out and assemble them into approximate rectangles. The perimeter of the rectangle is 8 cm longer than that of the original circle. What is the area of the rectangle in cm**2.
把一个圆平均分成偶数等份，剪开后拼成近似的长方形，长方形的周长比原来圆的周长增加8厘米，长方形的面积是多少cm**2．
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<gadget id="calculator">12.56 * 4</gadget>
<output>50.24</output>

<result>50.24</result>