If a wire just encloses a circle with a radius of 3 decimeters, what is the side length of a square?
一根铁丝刚好围成一个半径是3分米的圆，如果改围成一个正方形边长是多少分米．
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">2 * 3.14 * (3/4)</gadget>
<output>4.71</output>

<result>4.71</result>