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## Square or Round

 Puzzle ID: #1399 Fun: (2.31) Difficulty: (1.43) Category: Other Submitted By: stormcloud99 Corrected By: cowman12

Why are manhole covers round and not square?

### Hint

Think of what might happen if it was square.
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 friesx100 Nov 21, 2001 cool, good thinking Mike1313 Dec 03, 2001 actually, if you dropped it the way you describe it, it wouldn't fall in; it would catch on the corners. You would have to drop it on a diagonal through the hole with one of the flat sides of the square facing down. The square is widest at its diagonals. (user deleted) Jan 04, 2002 Also an equilateral triangle couldn't fall in the hole sireesht Jan 08, 2002 it not that reason for the manhole doors are mostly heavy i.e. bcoz to hold the loads for all vehicles and human etc. when it is to be pulled up easily and slided anywhere with less effort. more over the manhole has less area than the covering cap hence it won't fell down whether it is circle, square or even an equilateral triangle etc . when ever the sides are same of the polygon and it's area is greater than the manhole actual area it wont fall in. i am not a manhole repairer it's my logic and i am a computer engg. curly May 03, 2002 There are 2 reasons acctually, the other being that it's easier for workmen to move, Because it is round it can be rolled!! speedyg1000 Dec 12, 2002 how about because the whole is round? electronjohn Jan 17, 2003 All common shapes will fall in the hole, including equilateral triangles, except for the circle. This is a common job interview question and there are many other good answers to it, such as: For any given area a circle has the smallest circumerance so that there will be less area around the edges to stick, a circle cover is easy to replace since you do not need to turn it until the sides line up, easy to roll as already noted, and of course not falling in on itself. Crazycriely Jul 09, 2006 isnt this a trivia? Mac-Attack Mar 22, 2007 the hole could be bigger than the area of the lid. saxman May 07, 2007 There are 2 reasons acctually, the other being that it's easier for workmen to move, Because it is round it can be rolled!! Anyone who has ever actually handled a manhole cover will tell you it is both very difficult and unsafe to roll them. They weigh from 150 to 300 pounds, depending upon diameter and thickness, but they will definately put a hurt on an errant leg or foot if they fall over. The easiest (and safest) way to move them is by sliding them with a hook inserted in one of the holes. jasmin215 Oct 30, 2007 what is a manhole???? biztycl Dec 25, 2007 Well.. for those of you who don't know, this used to be a famous BCG Interview question