None. They either consist of curved sides or are not closed shapes (have lines "sticking out").
all letters
G
None in the Roman alphabet.
It depends on the alphabet:Latin = NONEGreek = ΔCyrillic = NONEHebrew = ם (depending on the font)Arabic = NONEKorean = NONEThere are also a few chinese characters that can loosely be described as polygons, such as: 凸凹口囗
A nonconvex polygon is a concave polygon. All polygons with 4 or more sides can be concave. An arrowhead is an example of a concave quadrilateral. The back of an envelop (where the sides are folded and glued together) is a concave pentagon.
The letters X L T
Not necessarily.
A triangle is normally nonconvex on a flat surface
No, there are 26 letters in the alphabet.
There are 26 letters in the alphabet.
The official Philippine alphabet has 28 letters.
the alphabet has 26 letters in it