Why do you think manholes are round in shape?
(You need to think a little crooked for this )
(In reply to
correct me if i'm wrong by Alan)
hey Alan.....just check your last line whare you have stated.........."If manholes were triangles they wouldn't try to fit them in circular holes they would fit them in circular holes".........which in fact should be........."If manholes were triangles they wouldn't try to fit them in circular holes they would fit them in triangular holes".
otherwise you are absolutely correct that if the manholes were of any other shape, then similar holes(of the same shapes as the shapes of their lids) would have been made and then could have been fitted..........but why even these do not work is given in my explanation for the topic........please do go through my answer..........