8,24,56,120,248,504,1016,2040,4088,8184,16376
,32760...
What do the numbers 3,9,15,21,27,33,39,45,51,57,63,69,75,81,87,93,99... when it comes to regular polygons have in common?
A visual construction of a regular nonagon with compass and marked ruler (neusis construction of a nonagon).
Start with a hexagon and triangle as a base,
√2+1 lines, one being the side of the regular octagon. |
√ 2 |
√ 2 |
a2 + b2 = c2. (√ 2+1)2 +(1)2 = c2 |
Lines of one |
a2 + b2 = c2. (√2/2)2 + (√2/2+1)2 =c2 |
Lines of 2 |