Draw a circle with a circumference of 31.4 cm, what is the distance between the two feet of the compass.
画一个周长是31.4厘米的圆，圆规两脚之间的距离是多少．
<gadget id="calculator">31.4 / 3.14 / 2</gadget>
<output>5</output>

<result>5</result>