If the diameter of circle A and the radius of circle B are both 4 cm, what is the circumference of circle A equal to the circumference of circle B?
如果甲圆的直径和乙圆的半径都为4厘米，那么甲圆的周长是乙圆周长的多少
<gadget id="calculator">3.14 * 2 * 4</gadget>
<output>25.12</output>

<gadget id="calculator">4 / 25.12</gadget>
<output>0.159236</output>

<gadget id="calculator">3.14 * 0.159236</gadget>
<output>0.500001</output>

<result>0.500001</result>