A 5-sided polygon is called a pentagon. You can draw up to 5 diagonals in a pentagon.
1/2*(142-42) = 77 diagonals
17
17
There are: 0.5*(682-(3*68)) = 2210 diagonals
7-3 = 4
38 diagonals
It is 18 diagonals
4
4...
A diagonal of a polygon is a segment drawn from one vertex to another non-adjacent vertex in a polygon. This leaves 32 diagonals that can be drawn from one vertex in a 35 sided polygon.
In a 54-sided polygon, 53 possible diagonals can be drawn from one vertex to another. These diagonals will not intersect. Therefore, the interior will be divided into 54 regions by the 53 diagonals plus the two sides of the original polygon that adjoin the vertex from which the diagonals are drawn.
5
1/2*(142-42) = 77 diagonals
170 diagonals
17
17
It is a 42 sided polygon and has: 0.5*(422-(3*42)) = 819 diagonals