Two iron wires of the same length form a rectangle and a square respectively. It is known that the length of the rectangle is 16 cm and the width is 13 cm. What is the length of the sides surrounding the square?
两根同样长的铁丝，分别围成一个长方形和一个正方形，已知长方形的长是16厘米，宽是13厘米．围成正方形的边长是多少厘米？
<gadget id="calculator">16 + 13</gadget>
<output>29</output>

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

<gadget id="calculator">29 * (1/2)</gadget>
<output>29/2 = around 14.5</output>

<result>29/2 = around 14.5</result>