After converting a circle into an approximate rectangle, the circumference increases by 20 cm. What is the circumference of the rectangle in cm?
将一个圆转换成近似的长方形后，周长增加了20厘米，这个长方形的周长是多少厘米．
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">3.14 * 10 * 2</gadget>
<output>62.8</output>

<gadget id="calculator">62.8 + 20</gadget>
<output>82.8</output>

<result>82.8</result>