by Owl Zero on July 18th, 2008

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How do you find the area of an octagon?

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Answers. 4 helpful answers below.

by LarryH54 on July 18th, 2008
Divide it into 8 triangles, and find the area of one of them. Times 8.
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- i subtract four intangible triangles from a dozen... same same though☺
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  by technios on July 18th, 2008
- Oh, there are LOTS of ways of doing it. You could also add two triangles into a trapezoid, multiply L*W, and multiply by 4.
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  by LarryH54 on July 18th, 2008
- Ummm... Okay, maybe not.
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  by LarryH54 on July 18th, 2008
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by NOYFB on July 18th, 2008
For a regular octagon, use this equation with t being the length of one of the edges.

Area = 4.828427*t^2
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- that would be too big it seems like???
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  by technios on July 18th, 2008
- Nope, not too big, not too small, just right.
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  by NOYFB on July 18th, 2008
- ahhh i see, from my first answer I was thinking that it should be smaller than 3*T^2... it still seems like that would be too big on first glance because i thought to myself 3*t^2 would be a square that encompassed the negative space as well... this one still makes me scratch my head☺
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  by technios on July 18th, 2008
- Think of it this way. If you put a circle inside of an octagon so that it touches all 8 sides, then the radius will be equal to the length of one of those sides. Draw it out and it will be obvious. So, 3.14*t^2 is the area of the circle, so the area of the octagon must be bigger because you are not taking into account all of the peaks outside of the circle.
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  by NOYFB on July 18th, 2008
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by technios on July 18th, 2008
s = side (s*2.41421356238)^2 - (s^2) i messed around with the numbers for a minute and i think this formula might work... can any one verify that this works or have i come up with another one that does not work??? please help
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- Yes, this works. Check it against my answer which is a simplified version of this equation.
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  by NOYFB on July 18th, 2008
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by technios on July 18th, 2008
(3*s)^2 - 4((s/2)*s) for an equal sided, s = side lenth
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- oops... this does not work☺ try this at home but not nasa
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  by technios on July 18th, 2008
- or maybe it does☺
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  by technios on July 18th, 2008
- nope
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  by technios on July 18th, 2008
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