hoey@ai.etl.army.mil (Dan Hoey) (07/21/88)
In article <624@uhnix2.uh.edu> uace0@uhnix2.uh.edu (Michael B. Vederman) writes: >Actually, If you don't know, it's because any other shape would either >be too much of a waste of area (such as a triangle) or the lid would be >able to fall through the hole and down into the bowels of the city! In article <4862@killer.DALLAS.TX.US> ltf@killer.DALLAS.TX.US (Lance Franklin) writes: >...a equilateral triangle for a manhole cover wouldn't >fall into the hole either. And in article <134@ai.etl.army.mil> richr@ai.etl.army.mil (Richard Rosenthal) writes: >Triangular (3 sided) covers cannot fall through the hole. But in fact you *can* slide an equilateral triangle through a hole of the same shape and slightly smaller size. You turn it sixty degrees and slide it through at the base of the hole. It works because the altitude of the triangle is less than the side. You can fudge it by making the cover thick enough, or making the ledge wider. You can fudge it with a square cover too--just make the cover in the shape of a cube. Dan
tomb@hplsla.HP.COM ( Tom Bruhns) (07/29/88)
The "Why are manhole covers round?" question used to be used very regularly as an interview question where I proviously worked. They said that they dropped that question when some guy they were interviewing started writing a list of reasons, and filled up a whole (was that "hole"?) page with serious (and generally correct) answers! Sorry I don't have the list to pass along :-)