Octagon
An octagon
An octagon or 8-gon is
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Regular octagon
All sides of a regular octagon are the same length. Each corner is 135°. All corners added together equal 1080°.
Area
The amount of space a regular octagon takes up is
![{\displaystyle {\text{Area}=2(1+{\sqrt {2})a^{2}.}](https://wikimedia.org/api/rest_v1/media/math/render/svg/9949a68f0055c94692bc8a33fe0ce97cbd4670b5)
a is the length of one of its sides.
Another way to write it is
![{\displaystyle {\text{Area}=2a^{2}({\sqrt {2}+1).}](https://wikimedia.org/api/rest_v1/media/math/render/svg/9eda9346e3bb86ed1967a9370551bd908848951c)
Gallery
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This shape is called an octagram. It has one regular octagon in the middle.
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The octagonal prism has 2 octagons in it: one on the top, and the other on the bottom.
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A non-regular octagon
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Making an octagon by folding paper
Related pages
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Special cases, including regular polygons with their own names, in parentheses List of polygons by number of sides |
1–10 sides | | |
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11–20 sides | |
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21–30 sides | |
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31–50 sides | |
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51–100 sides (selected) | |
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>100 sides | |
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Star polygons (5–12 sides) | |
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Triangles | |
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Quadrilaterals | |
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