no
a decogon
8
If decogon were a real word then the prefix would, could be de-, dec- or deco-. But it is not a real word and so there is no prefix.
12
A decagon has 10 sides
Decogon * * * * * A decagon, actually.
it is a ten sided and ten angled figure
10 side polygon is called decogon
There is no such shape as a decogon. There is a decagon, which is a ten-sided polygon.Each interior angle of a decagon can have any value in the range (0, 360) degrees excluding 180 degrees. The only restriction is that the sum of all the interior angles is 1440 degrees.
None because there is no such figure. A decagon, on the other hand, has just one face.
A decagon is a polygon with 10 sides and 10 angles. Deca is from the Greek meaning of "ten".