There is a rectangle surrounded by iron wire with a length of 7 decimeters and a width of 3 decimeters. If this wire is used to form a square, what is the side length of the square?
有一个用铁丝围成的长方形，长是7分米，宽是3分米，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．
<gadget id="calculator">7 + 3</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>