Naughty tied a round plastic rod with a base diameter of 2 cm and tied it 10 times with ribbons. If the interface is not counted, how many meters is the length of the ribbon?
淘气把一根底面直径为2厘米的圆形塑料棒用彩带捆了10圈．如果接口处不计算，彩带长多少米？
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">3.14 * 2 * (1/10)</gadget>
<output>0.628</output>

<result>0.628</result>