Search: 11 sided polygon
Why: Sadie's placemat has various shapes on it, but none have 11 sides.
Answer: Hendecagon! And an 11-sided polyhedron is called a hendecahedron. It might look like this:
Source: Mathforum.org
The More You Know: Here are some other names:
- 9 - enneagon
- 12 - dodecagon
- 13 - triskaidecagon
- 14 - tetrakaidecagon
- 19 - enneakaidecagon
- 20 - icosagon
- 21 - icosikaihenagon
- 22 - icosikaidigon
- 23 - icosikaitrigon
- 30 - triacontagon
- 31 - triacontakaihenagon
- 32 - triacontakaidigon
- 40 - tetracontagon
- 50 - pentacontagon
- 100 - hectogon
- 1000 - chiliagon
- 10000 - myriagon
