After cutting a circular piece of paper, assemble it into an approximate rectangle whose width is equal to the radius and whose area is constant. The perimeter of this rectangle is 33.12 cm. What is the area of this circle?
把一个圆形纸片剪开后，拼成一个宽等于半径、面积不变的近似长方形，这个长方形长的周长是33.12cm，这个圆形的面积是多少？
<gadget id="calculator">2 * 3.14</gadget>
<output>6.28</output>

<gadget id="calculator">6.28 + 2</gadget>
<output>8.28</output>

<gadget id="calculator">33.12 / 8.28</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>