piece of iron wire can exactly form a rectangle with a length of 12 cm and a width of 6 cm. If it is reshaped into a square, what is the side length of the square in centimeters?
一根铁丝正好可以围成一个长12厘米，宽6厘米的长方形．若将它改围成一个正方形，这个正方形的边长是多少厘米．
<gadget id="calculator">12 + 6</gadget>
<output>18</output>

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

<gadget id="calculator">18 * (1/2)</gadget>
<output>9</output>

<result>9</result>