Question 1164700
<pre>

0 sides and 0 diagonals.  In other words, the polygon is degenerated into a
single point, which has no sides and no diagonals.  In higher geometry courses
that is allowed.  But in lower level geometry it is not.  If you are in a
lower level of geometry, then the answer is "There are no such polygons,
because there must always be 2 fewer diagonals than sides".

Edwin</pre>