Math Wizzez, I need your help...

ckinney

Active member
339
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I am working on getting my back yard together and would like to have a 12 foot octagon, can't remember how to calculate the length of each side, can anyone help me out on this one? or know a good web based calculator for this?

Thanks in advance - Chris
 

rynofan23

Active member
171
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I'll give this a try.

The angle from the center to a middle of one of the sides would be 22.5 (180/n). The radius of your octagon is 72", which would make this the adjacent side. What we need to figure out is the opposite side. Using a trigonometry function, we can find the opposite side by using 2 x radius x tan 22.5. This gives us 59.64675".

I'll let someone check my work. It's been a decade since I've done any trig.

Tai

By the way, I'm assuming 12' is going across.
 

ckinney

Active member
339
4.90 star(s)
I'll give this a try.

The angle from the center to a middle of one of the sides would be 22.5 (180/n). The radius of your octagon is 72", which would make this the adjacent side. What we need to figure out is the opposite side. Using a trigonometry function, we can find the opposite side by using 2 x radius x tan 22.5. This gives us 59.64675".

I'll let someone check my work. It's been a decade since I've done any trig.

Tai

By the way, I'm assuming 12' is going across.

Thanks - yes the 12' is going from one side to the other, not the points... if that changes anything...
 

rynofan23

Active member
171
5.00 star(s)
Thanks - yes the 12' is going from one side to the other, not the points... if that changes anything...

Nope, nothing changes. Here's my handy work if you care to see it. :p



Tai
 

ckinney

Active member
339
4.90 star(s)
That is awesome, thank you so much.

I can now get started on another "honey-do"

Yet another reason why I absolutely love this site.

- Chris
 
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