After dividing a circle into several equal parts, put together an approximate rectangle. The width of this rectangle is 5 centimeters. What is the perimeter of this rectangle in centimeters.
把一个圆平均分成若干份后，拼成一个近似的长方形，这个长方形的宽是5厘米，这个长方形的周长是多少厘米．
<gadget id="calculator">2 * 3.14 * 5</gadget>
<output>31.4</output>

<gadget id="calculator">31.4 / 2</gadget>
<output>15.7</output>

<gadget id="calculator">15.7 + 5</gadget>
<output>20.7</output>

<gadget id="calculator">20.7 * 2</gadget>
<output>41.4</output>

<result>41.4</result>