Why do men and women's clothing fasten on opposite sides?
I don't know why they are different in western societies, but I do know why the male's clothes fasten the way they did. In a society of right handed people, warriors carried their sword on their left hip. If they pulled it out and the hilt snagged in the buttons, he could end up dead. So the overlap was made left over right.
blame the kings and queens for that one, back in midevil times, the kings dressed themselves, the queens and princesses were dressed by servants, usually male. therefore the male buttons, zips, and belts on the right, for the right handed, while the womens is always to the left, because it would be the right hand of the male servent dressing her.
It goes back in time when wealthy people had butlers, and maids to help them to dress: men normally dressed themselves but ladies had other women to help them dress and women naturally had clothing buttons reversed to help maids clothe them. And, the tradition continues to this day with the reversed buttons on women's clothing.
a decagon i believe has either 5 or 20 opposite sides * * * * * A decagon has 10 sides so I cannot see how it could have 20 opposite sides. It has 5 pairs of opposite sides but this does not mean that these opposite sides face each other. In an irregular decagon it is quite possible for opposite sides to be at right angles or at any angle to each other.