Ok well for quadrilaterals a parallelogram is a 4 sided figure with 2 sets of parallel sides and a trapezoid is a 4 sided figure with 1 set of parallel sides.

So is there a name for a quadrilateral with 0 sets of parallel side?



The answer depends on which side of the Atlantic you live.

In North America A trapezoid is a quadrilateral that has exactly two parallel sides; a trapezium is a quadrilateral with no sides parallel. (Actually, I BELIEVE that both of these must be convex, which means that all angles have to be less than 180 degrees, but I have seen no authoritative source for such a restriction.)

In Britain the meanings are reversed (the trapezium has 2 parallel sides and trapezoid none).

Thus, when it is important to be unambiguous, one should avoid the terminology and say precisely how many parallel sides there are. You can find the history of this unfortunate state of affairs in the Oxford English Dictionary.

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