never - the only thing it may have is common is that a simple rectangle will have four right angles. But a rectangle is not simple, it is complex.
Fact there IS such thing as four sided triangles, no they aren't polygon's yes they are triangles, do some research on it?
Four factors in common.
Most common is the thing that happens most, and least common is the least ocuring thing. For example it is most common to open chess with middle pawn forward. And it is least common to move one of the far pawns first.
Four of them.
transistors
Ice cubes
Mutation, Reproduction.
Orographic lifting
Wind, water, animal, and mechanical
there are many different types of mechanisms that can make thing cross cell membranes two of these are by diffusing and active transport.
species have members that share common fertilization mechanisms.
biometrics digital certs secureid
The noun four is a singular, common noun; a word for a number, a thing. Numbers are both nouns and adjectives; examples: Noun: The correction has been made to page four. Adjective: It's a four page report.
As far as the round rubber thing a car has four of on it's wheels, yes, it is a common noun. It is also a verb, meaning "to become fatigued".
the four common habitat are ponds
Four common contraindication in make-up