An iron wire can form a circle with a diameter of 4.5 decimeters. If this iron wire is folded into an equilateral triangle, what is the side length of this triangle?
一根铁丝，可以围成一个直径为4.5分米的圆，如果把这根铁丝折成一个等边三角形，这个三角形的边长是多少分米？
<gadget id="calculator">4.5 / 3</gadget>
<output>1.5</output>

<gadget id="calculator">3.14 * 1.5</gadget>
<output>4.71</output>

<result>4.71</result>