Re-enclose a rectangular iron frame with a length of 8 decimeters and a width of 40 cm to form the largest square iron frame. What is the side length of this square iron frame?
把一个长8分米，宽40厘米的长方形铁架重新围成一个最大的正方形铁架，这个正方形铁架的边长是多少分米？
<gadget id="calculator">40 / 10</gadget>
<output>4</output>

<gadget id="calculator">8 + 4</gadget>
<output>12</output>

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

<gadget id="calculator">12 * (1/2)</gadget>
<output>6</output>

<result>6</result>