A piece of iron wire can exactly form a rectangle with a length of 5 decimeters and a width of 3 decimeters. If this wire is used to form a square, what is the side length of this square?
一根铁丝正好能围成一个长5分米、宽3分米的长方形，如果用这根铁丝围成一个正方形，这个正方形的边长是多少分米？
<gadget id="calculator">5 + 3</gadget>
<output>8</output>

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

<gadget id="calculator">8 * (1/2)</gadget>
<output>4</output>

<result>4</result>