To draw a circle with a circumference of 25.12 cm, what is the distance in cm between the two feet of the compass.
要画一个周长是25.12cm的圆，圆规两脚间的距离是多少cm．
<gadget id="calculator">25.12 / 3.14 / 2</gadget>
<output>4</output>

<result>4</result>