Xiaogang uses an iron wire to form a rectangular parallelepiped frame. This rectangular parallelepiped frame has a length of 9dm, a width of 5dm, and a height of 4dm. If this iron wire is used to form a rectangular parallelepiped frame, how many decimeters is the edge length of this cube frame?
小刚用一根铁丝围成一个长方体框架，这个长方体框架长9dm，宽5dm，高4dm，如果用这根铁丝围成一个正方体框架，那么这个正方体框架的棱长是多少分米？
<gadget id="calculator">9 + 5 + 4</gadget>
<output>18</output>

<gadget id="calculator">4 / 12</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">18 * (1/3)</gadget>
<output>6</output>

<result>6</result>