A wire encloses a circle with a diameter of 8 decimeters. If it forms a square, what is the length of its side?
一根铁丝正好围成一个直径8分米的圆，如果围成正方形，它的边长是多少分米
<gadget id="calculator">8 / 4</gadget>
<output>2</output>

<gadget id="calculator">3.14 * 2</gadget>
<output>6.28</output>

<result>6.28</result>