The diameter of circle A is 8 cm long, which is (2/5) the diameter of circle B. What is the circumference of circle B.
甲圆直径长8厘米，是乙圆直径的(2/5)．乙圆的周长是多少．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">8 / (2/5)</gadget>
<output>20</output>

<gadget id="calculator">3.14 * 20</gadget>
<output>62.8</output>

<result>62.8</result>