For a cylinder, the distance between the two bases is 10 cm, and the perimeter of the base is 31.4 cm. Expand the sides of the cylinder to obtain a rectangle. What is the perimeter of the rectangle?
一个圆柱体，两底面之间的距离是10厘米，底面周长是31.4厘米，把这个圆柱体的侧面展开得到一个长方形，长方形的周长是多少．
<gadget id="calculator">31.4 + 10</gadget>
<output>41.4</output>

<gadget id="calculator">41.4 * 2</gadget>
<output>82.8</output>

<result>82.8</result>