For the safety of handling, put two rubber protective rings on an oxygen cylinder with a diameter of 20 cm and a height of 1.5 meters. How many meters of rubber belts are needed in total?
为了搬运安全，给一个直径20厘米、高1.5米的氧气瓶套上两个橡胶保护圈，一共需要橡胶带多少米？
<gadget id="calculator">2 / 100</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">3.14 * 20 * (1/50)</gadget>
<output>1.256</output>

<result>1.256</result>