Two iron wires of the same length are welded to a cuboid and a cube. The cuboid is 7 cm long, 5 cm wide, and 3 cm high. What is the side length of the cube in cm?
两根同样长的铁丝焊一个长方体和正方体，长方体长7厘米，宽5厘米，高3厘米，正方体的棱长是多少厘米？
<gadget id="calculator">7 + 5 + 3</gadget>
<output>15</output>

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

<gadget id="calculator">15 * (1/3)</gadget>
<output>5</output>

<result>5</result>