Some pools are made in the shape of a nonagon. The Baha'i House of Worship in Wilmette, Illinois is also a nonagon.
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.
a nonagon
A nonagon.
A nonagon has nine sides.
A nonagon
"nonagon" is not a prefix.
Nonagon.
A nonagon is a 2D shape so you cannot make a 3D nonagon!