A piece of iron wire just surrounds a rectangle with a length of 8 cm and a width of 2 cm. If this wire surrounds a square, what is the side length of the square?
一根铁丝刚好围成一个长为8厘米，宽为2厘米的长方形，如果用这根铁丝围城一个正方形，正方形的边长是多少厘米？
<gadget id="calculator">8 + 2</gadget>
<output>10</output>

<gadget id="calculator">2 / 4</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">10 * (1/2)</gadget>
<output>5</output>

<result>5</result>