After dividing a circle into several equal parts, put together an approximate rectangle. If the width of the rectangle is 5 cm, what is the length in cm?
把一个圆平均分成若干份后，拼成一个近似的长方形，已知长方形的宽是5厘米，则长是多少厘米．
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 5 * 1</gadget>
<output>15.7</output>

<result>15.7</result>