If the sum of the lengths of the sides of a cuboid is 60 cm, what is the sum of the lengths of the three sides that intersect at a vertex?
一个长方体的棱长总和是60厘米，相交于个顶点的三条棱长的总和是多少厘米．
<gadget id="calculator">60 / 4</gadget>
<output>15</output>

<result>15</result>