Divide a circle into several parts and put together an approximate rectangle. The length of this approximate rectangle is 6.42 decimeters more than its width. What is the area of this rectangle in square decimeters?
把一个圆分成若干份，拼成一个近似长方形，这个近似长方形的长比宽多6.42分米，这个长方形的面积是多少平方分米．
<gadget id="calculator">6.42 / 2.14</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<result>28.26</result>