Divide a circle into several equal parts along the radius, and then put together an approximate rectangle. The length of this rectangle is measured to be 9.42 cm. Find the area of the original circle.
将一个圆沿半径分成若干等份，再拼成一个近似的长方形，量得这个长方形的长是9.42cm，求原来圆的面积．
<gadget id="calculator">9.42 / 3.14</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>