Put together a circle to form an approximate rectangle. If the width of this rectangle is 2 cm, what is its length in cm?
把一个圆形拼成一个近似的长方形，如果这个长方形的宽是2厘米，他的长是多少厘米．
<gadget id="calculator">3.14 * 2</gadget>
<output>6.28</output>

<result>6.28</result>