Octagon (EntityTopic, 12)
From Hi.gher. Space
An octagon is a polygon with 8 sides. It is the truncated square.
Coordinates
The coordinates of a regular octagon with side two are all permutations of:
(±1, ±(1+√2))
Equations
- The area of a regular octagon with side length l is:
2(1 + √2) · l^{2}
Dissection
The octagon of side 1 may be dissected into 8× isosceles triangle with sides {1,2×√(1+^{√2}⁄_{2})}.
Incidence matrix
Usage as facets
- prism: 2× 1-facets of a octagonal prism
- 6× 1-facets of a truncated cube
- 6× 1-facets of a stauropantohedron
- 1× 1-facets of a square cupola
Notable Dishapes | |
Flat: | triangle • square • pentagon • hexagon • octagon • decagon |
Curved: | circle |