If the cross-section of the trunk of a tree is a circle and its circumference is 62.8 cm, what is its diameter in cm?
如果一棵树的树杆的横截面是一个圆，它的周长为62.8厘米，那么它的直径为多少厘米．
<gadget id="calculator">62.8 / 3.14</gadget>
<output>20</output>

<result>20</result>