Divide a circle into several equal parts, and then assemble it into an approximate rectangle. It is known that the width of the rectangle is 2 centimeters, and the length of the rectangle is how many centimeters.
把一个圆平均分成若干等份，然后把它拼成一个近似的长方形，已知长方形的宽是2厘米，长方形的长是多少厘米．
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 2 * 1</gadget>
<output>6.28</output>

<result>6.28</result>