Divide a circle into several equal parts and form an approximate rectangle with a radius of . The perimeter of this rectangle is 8.28 cm. What is the area of this circle?
将一个圆平均分成若干份，拼成一个以半径为的近似长方形，这个长方形的周长是8.28厘米，这个圆的面积是多少．
<gadget id="calculator">1 + 3.14</gadget>
<output>4.14</output>

<gadget id="calculator">8.28 / 2 / 4.14</gadget>
<output>1</output>

<gadget id="calculator">1 ** 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 1</gadget>
<output>3.14</output>

<result>3.14</result>