Why is a manhole cover round?

Question

Anyone know why???????????

Answer 1

My underwear is not round.

Answer 2

There is a possibility for the corner of a square manhole to jut out making it a road hazard.

...but if you want t to be funny about it--so that the round cover will fit into the round hole.

Answer 3

Because the manhole entry itself is round.

Answer 4

That way no matter what way you spin the man hole cover it cannot fall through the open hole.

Spin a square manhole cover on the diaganol and it will fall in.

Answer 5

Because under street and cover is a round pipe.
That goes straight down and connects to another pipe that goes under road way and carries sewer to plant or lift station

They are not that heavy I work at construction company and take them off sometimes.
They might weigh 50-70 pounds max

Answer 6

Probably to prevent knuckleheads from taking it off and dumping it down the hole. You could do that with a square or almost any other shape, but a circle is almost impossible..
Also, being round, you can roll it if you have to move it.

Answer 7

So it doesn't fall in the hole. An equilateral triangle wouldn't either but a circle that weighs 200 pounds is easier to line up over a hole than a triangle.

Answer 8

That's easy, so it won't fall into the manhole .

Answer 9

Uhhh... so you don't have to worry about lining it up when trying to put it back in place? A circle plops right back into place... any other shape would have to be twisted and aligned. Not easy to do with something that weighs as much as 150 pounds.

Answer 10

because if it would have been square you would have asked "Why is a manhole cover square?"