A circle with a diameter of 2 meters is formed with a piece of iron wire. What is the length of the wire in meters?
用一根铁丝正好围成一个直径2米的圆，这根铁丝长多少米．
<gadget id="calculator">3.14 * 2</gadget>
<output>6.28</output>

<result>6.28</result>