41 replies to this topic

[rookie1ja]

Round vs. Square - Back to the River Crossing Puzzles
Why is it better for manhole covers to be round rather than square?

This old topic is locked since it was answered many times. You can check solution in the Spoiler below.
Pls visit New Puzzles section to see always fresh brain teasers.

Spoiler for Solution

Round vs. Square - solution
You can turn a square manhole cover sideways and drop it down the diagonal of the manhole. You cannot drop a round manhole cover down the manhole. Therefore, round manhole covers are safer and more practical than square ones.

[larryhl]

another interview question =)

[darksquid]

The obvious answer is that manhole covers should be round because manholes are round.

But your answer is more informative.

[Veracity]

Correct-a-mundo!!! There is not a single shape (besides perfectly round) that could not be positioned in a way that would cause it to fall in the hole. None what-so-ever! It's funny to think that even Manhole Covers were thought out well before mass production began. You would just think they were round because they were going on a ROUND HOLE...lol

Also, seeing as how the damn things weigh about 38 gazillion pounds, trying to lift one is not an easy task. The method to move them typically is "Rolling them". Needless to say, trying to ROLL a 4 edged square hunk of metal would

[rockypg]

Correct-a-mundo!!! There is not a single shape (besides perfectly round) that could not be positioned in a way that would cause it to fall in the hole. None what-so-ever! It's funny to think that even Manhole Covers were thought out well before mass production began. You would just think they were round because they were going on a ROUND HOLE...lol

Also, seeing as how the damn things weigh about 38 gazillion pounds, trying to lift one is not an easy task. The method to move them typically is "Rolling them". Needless to say, trying to ROLL a 4 edged square hunk of metal would <!-- s:oops: --><!-- s:oops: -->

Veracity, the veracity of your statement is suspect:
"There is not a single shape (besides perfectly round) that could not be positioned in a way that would cause it to fall in the hole." , You couldn't be more wrong!

heard of "constant diameter curves" ?
A circle is just one of many such curves:
read This
and This

That said, you are bang on target with your second statement about the ease of rolling

R

[Veracity]

Correct-a-mundo!!! There is not a single shape (besides perfectly round) that could not be positioned in a way that would cause it to fall in the hole. None what-so-ever! It's funny to think that even Manhole Covers were thought out well before mass production began. You would just think they were round because they were going on a ROUND HOLE...lol

Also, seeing as how the damn things weigh about 38 gazillion pounds, trying to lift one is not an easy task. The method to move them typically is "Rolling them". Needless to say, trying to ROLL a 4 edged square hunk of metal would

Veracity, the veracity of your statement is suspect:
"There is not a single shape (besides perfectly round) that could not be positioned in a way that would cause it to fall in the hole." , You couldn't be more wrong!

heard of "constant diameter curves" ?
A circle is just one of many such curves:
read This
and This

That said, you are bang on target with your second statement about the ease of rolling

R

Well, Look at that.. Your right. I stand corrected. I love learning new things. Thank you for taking the time to add a link to back your reasoning up....!!

[htyphoon]

While it may not be correct that it is the only shape that won't fall through the hole, it appears to be the only one that won't fall through and actually serves the purpose of a manhole cover -- to cover the manhole. Of course, if you were just trying to prove someone wrong so you looked smart, congrats!

Dave

[Veracity]

While it may not be correct that it is the only shape that won't fall through the hole, it appears to be the only one that won't fall through and actually serves the purpose of a manhole cover -- to cover the manhole. Of course, if you were just trying to prove someone wrong so you looked smart, congrats!

Dave

LOL
I wasn't going to say anything figuring if I had it would look like I was Making Excuses to Justify my being Incorrect... But since you mentioned it...lol

[mathemagister]

One of the English' coins is a condiam (constant diameter curve).

[speshall mareens]

a round lid covers more area of the square then a square lid to help from it leaking (why they dont want it to leak its a sur) and you can roll it out of the way making it easier.