Divide a circle into several sectors and cut them into a rectangle whose width is equal to the radius and equal to the area. The perimeter of this rectangle is 24.84 cm. What is the area of the circle in square centimeters?
把一个圆分成若干个扇形剪开拼成一个宽等于半径，面积相等的长方形，这个长方形的周长是24.84厘米，圆的面积是多少平方厘米．
<gadget id="calculator">24.84 / 8.28</gadget>
<output>3</output>

<gadget id="calculator">3.14 * 3 * 3</gadget>
<output>28.26</output>

<result>28.26</result>