Dad used wire to form a rectangular frame with a length of 10 cm and a width of 8 cm, and later changed it into the largest square. What is the side length of this square in cm?
爸爸用铁丝围成一个长10厘米，宽8厘米的长方形框架，后来把它改成一个最大的正方形，这个正方形的边长是多少厘米．
<gadget id="calculator">10 + 8</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>