A wire can form a circle with a diameter of 10 cm. If it is used to form a square, what is the side length of the square?
一根铁丝可以围成一个直径是10厘米的圆，如果用它围成一个正方形，正方形的边长是多少厘米．
<gadget id="calculator">10 / 4</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">3.14 * (5/2)</gadget>
<output>7.85</output>

<result>7.85</result>