Use an iron wire to form a rectangle with a length of 15 cm and a width of 13 cm, and then straighten the wire to form a square. What is the side length of this square in cm?
用一根铁丝围成一个长15厘米，宽13厘米的长方形，再把这根铁丝拉直围成一个正方形，这个正方形的边长是多少厘米？
<gadget id="calculator">15 + 13</gadget>
<output>28</output>

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

<gadget id="calculator">28 * (1/2)</gadget>
<output>14</output>

<result>14</result>