Xiaoxiao draws a circle with a diameter of 20cm with a compass. What is the circumference of this circle in cm?
笑笑用圆规画了一个直径是20cm的圆，这个圆的周长是多少cm．
<gadget id="calculator">3.14 * 20</gadget>
<output>62.8</output>

<result>62.8</result>