You add together the lengths of the nine sides of the nonagon.
nonagon
Because nonagon means 9 sides
Not a regular nonagon.
Add the length of all nine sides up.
Only if all nine sides are the same length.
A nonagon is a 2D shape so you cannot make a 3D nonagon!
Nonagon.
A nonagon has nine sides.
A nonagon.
a nonagon
A nonagon