What is the circumference of a circular piece of paper with a radius of 5 cm after cutting half a circle?
把一张半径5厘米的圆形纸片剪掉半个圆后，它的周长是多少．
<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">2 * 5</gadget>
<output>10</output>

<gadget id="calculator">15.7 + 10</gadget>
<output>25.7</output>

<result>25.7</result>