How to draw a regular octagon knowing the length of one side

How to construct a regular 8-sided polygon given the measurement of one side.
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This RUclips channel is dedicated to teaching people how to improve their technical drawing skills. It focusses on drawing figures from the geometric plane to descriptive geometry and also different systems of technical drawing representation.
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Dubbed by Frank Shaw.
Music by Antonio Fernández Ruiz. antoniofernandez.es/
#Geometry #HowtoDraw

[@williamowens3905]

I needed an octagon for making a finial for the turret of my house. Precision is the key. Thanks so much!

[@anikawessels9714]

I saw the intro and drew it and was like ohh oops

[@riyachauhanriyachauhan3567]

Same thing with me 😁😁

[@cyber_bones1298]

yeah me too🤣😅

[@ashishrajput23]

Hi

[@troubiga]

😭 😭 😭 😭 intro got me 2

[@astro_penguin_]

It's not regular. I got 7 correct sides and 8th side is far too short. Noticed a lot of people had the same problem. And I did do everything properly.

[@akhilakhi3218]

Draw that from another side 👍

[@suminazar1387]

Mee too

[@HarshG28]

​@@akhilakhi3218 tried that too

[@hemlaprasad643]

Thanks a lot helped me in my basic technology test

[@sheikyassim4944]

Hey Aurther thanks and I like you because you well and explain How to construct these

[@anthonypaul3609]

All your videos helps alot

[@kevingarner1558]

Thanks, I learned a lot.

[@neoxanimator6579]

Thank you man!

[@sheikyassim4944]

This video helped alot man!!!! Thank you

[@ANIRUDHJAGANATHANBME]

This helped me so much. Thanks a lot

[@chandandey5770]

Love u...bro...thank u for help us ........

[@hutumschool2737]

Easy to understand 🖒

[@evaperez7668]

omg thank uu soo much Arthur!!

[@victoroc7317]

thanks i enjoyed the video it really helped am greatful

[@iatemyhand11]

Thanks for the video, i like it

[@meenumehta874]

It solved my problem....... thanks a lot

[@za_opticzz2447]

Bro you are a g this has helped me so much ty

[@mic4059]

This helped SO much. Thank You Arthur!!

[@preasadpreasad4436]

Hii

[@Eggzzzo]

Hi

[@pritamreacted5962]

very helpful video ..................
thanks man.......

[@basilebannister710]

Thanks so much for this great video it helped me so much

[@utsabsenchury5152]

good

[@magdalenazumbira-zf4nq]

This will really help me alot

[@sunnahwear7540]

Anyone else gettting up to the part where u cut the circumference at 7 points but the last point dosent overlap A?
And yes I have checked over all calculations multiple times

[@Braycali]

Thank you.

[@a10cgaming67]

Octagon has 8 amazing sides and 8 fantastic angles

[@cc12yt]

oh.... *stop.*

[@sandippandit8256]

Octagon basic test helps.... Thank

[@voidstiles9654]

Yh it help me a lot thanks so much

[@almirkaqiu3776]

Thank you so much it helpt me with my math you are a genius

[@murthacharihkmurthyhk5075]

Thanks sir best video

[@valentin5403]

Something very important is missing here . Without it the above description is simply a recipe for constructing a regular octagon.

[@harryinhuahin1272]

"...the above description is simply a recipe for constructing a regular octagon."
What else did you expect...?

[@valentin5403]

@@harryinhuahin1272 the proof

[@thiengen3426]

Thanks a lot

[@probablynothung8135]

Good for a beginner. All u have to do is be creative.

[@yeshuakebede]

Bruh thank you so much!

[@sandippandit8256]

Thank you

[@shakeelmuhammad7192]

Excellent 👍, but little difficult for basic learner and beginner.
But it's excellent 😊

[@theresescicluna1601]

ITS the best vedeo if u want to learn

[@G_Silent]

Amazing never knew you could do this!

[@satrickptar6265]

Watching every polygons because they will appear on the test in no time

[@AmanDeep-hp6pf]

thanks a lot

[@ivantv7572]

THANK YOU

[@officialwarren825]

Thanks you

[@akashsharma7253]

Nice video sir

[@ashleybarnes6362]

Thanks lad

[@meenudas25]

Thankyou 🥰🥰

[@hMpP32]

beautiful

[@iatemyhand11]

Yeah, you're right. beautiful artwork of the octagon

[@everythinginonevines443]

Thanks sir

[@randallbegay9162]

Will it work for laying out a string line on Navajo hogan house ? Does dirt ground has to be flat level for this to work ?

[@suryateja4855]

How did you reduce the length to 3.40 cm?

[@zainabibrahim2889]

Wonderful v6

[@ericaanglin262]

I was hoping you could help me with some measurements. I want to make a 70 foot octagon that is divided equally by 24 inches across it's length, but need to calculate the individual lengths across the Octagon. I hope I've said that so you understand what I mean.

[@LockeAnimations]

chatgpt dude

[@YTShuaib]

Thank you very much :)

[@iatemyhand11]

Yeah, thank you very much

[@claudiaosorio9605]

If I only have an x circumference, how do I find the given measure to find the a b distance? Basically how do I divide any circumference to create a perfect octagon from it?

[@ArthurGeometry]

Try with this video: ruclips.net/video/7Y2ngw0UPo8/видео.html

[@jigssscupid8836]

Why scribe arcs N &O and why bisect line A B???

[@AswajithBabuAswajithBabu]

Why is that I got same result in both methods, this and by the method of taking angle 135..?
Same result in the sense, 7 sides are of required length and one side is short of the required length..
I tired drawing for 5 cm

[@DarkDevils2003]

Do manage to solve it? I also get the last side to be slightly shorter.

[@pineappleprincess9704]

An octagon is a shape with 8 sides, right?

[@ArthurGeometry]

Yes, It is

[@samiegapeters2503]

Spot on, thanks

[@user-pz2fe7en7c]

Kindly show how to draw ovtogonal patals.

[@subhodipdas3723]

What is the method name sir?

[@anuragpatil2338]

Why people unlike this?

[@achintyadwivedi1507]

Thanks a lot It just took 5 minutes to draw a single shape..

[@zagmek]

This was awesome for cutting some cardboard into an octagon to disguise an xmas white elephant gift! Everyone is going to think it's a stop sign!

[@shortclips4085]

Which method is this ??

[@kukukemokemo5279]

جميل جداً

[@suryateja4855]

Please mention it clearly .... How much you have taken the length...

[@dkgaming9467]

Thanks for the video I prepared for exam

[@valkeitos]

Cut section in EGD is a nightmare 🙇🏻‍♂️

[@2-_]

How, Elmo, how‽

[@LeClusterFunk]

Totally forgot to bring an octagon!

[@fergusb2440]

Radiuses? Or perhaps more appropriately, Radii?

[@pamkaur17]

Ok

[@diptikar9367]

This helped me for exam a lot

[@rashisharma8389]

Thx you help me in cheating in exams 😂😂

[@vutlharhimahatlani8557]

I can’t get it right

[@portaobellomushroom9198]

Mood

[@Dunc2222]

This is interesting, and I suppose may be useful if you only need to draw an octagon. But it would be much more helpful and educational if you provided some explanation of the principles that are behind this geometry. As it is, it feels like a superficial solution.

[@surajmahto9690]

Pentagon please give me

[@carlkundan8178]

im getting so comufes

[@RJ-vs5pt]

Thnx a lot sir

[@jotgill8481]

Nice 😋

[@radekutherknapcok5409]

I study math and I really like your videos, however sometimes I would really appreciate some more detailed info, as I am a person who want to know what is hidden behind "this magic" and how things really work. If you have some webpages or videos where you speak about proofs and so on please let me know.

[@posttenebraslux7571]

Watching the person drawing that on a computer is frustrating, I watched another video with a man drawing an octagon the normal way, by hand, accurate measurements, that was very satisfying for me.

[@valentin5403]

The ancient Greeks did not leave us just recipes. They left us the method of making proofs to any math problem. That's how I was thought to do geometry problems. First you show the proof (why point O is the center of circle and so on) then you display the construction. Logics originated in Greece only and later combined with Galileo experiments led to the scientific method. As such the scientific method is the crown achievement of the Western civilization.

[@Jjsticks._.]

WHERE IS JACK BLACK

[@TheHirou]

If your octagon looks like shit try this method instead, that honestly, works better:
-Draw a square.
-Divide that square into 4 squares, you can get the center point by getting the mediatrix using two of the sides.
-Draw an X that connects all 4 corner of the square.
-In the point marked by the X (The square center) draw a circle whose radius is half the entire square.
-The points in the circle that intersect with the X are the different corners of the octagon, draw a line in between them.

[@nnodimojukwu5941]

Pls what is the length of L

[@ArthurGeometry]

4cm.

[@nnodimojukwu5941]

@@ArthurGeometry thanks alot

[@luiginodilenardo6820]

Guarda
Miei disegni
Sono misurati
Riguardano area cerchio

[@lynnyac5664]

I made one mistake and ended up with a heptagon!

[@alnomanrafiz5043]

thanks

[@mariaortega9611]

That will take long

[@dhrubajyotidaityari9240]

Beauty

[@fgtnpjln4833]

Actagon

[@PeterTschappler]

Didn’t work, ended up with 9 1/2 sides after doing it perfectly

[@colinaugustyn3]

I need to draw a octagon 4 cm per side this method does not work

[@ArthurGeometry]

Yes, it works

[@colinaugustyn3]

Its a side short, is there a limit to how short the sides can be or no?

[@rob7290]

Please get a pop filter for your microphone.

[@harryinhuahin1272]

If only we could also get filters for silly and/or arrogant comments... lol

[@alfiyaalfiya4568]

I don't come this octagon

[@mehmedmehmed4553]

Vvv

[@carlkundan8178]

sssssssoooooooooo bad im getthing comu..
fffffff

[@eliasrodriguez895]

The way yo you teaching is difficult. I only have seventh grade school never took geometric class, easy whay drew a circle then use compass to divide the space you teaching is difficult

[@carlkundan8178]

i dont like math

[@legendddx16]

lawra

[@siennahenderson1812]

that is stupid ness

[@MustardPipeLibrary]

If there is any way in which this could be said to be "stupid", it is in not including a proof with the construction (which doesn't seem to be the point of this video anyway). I'll go ahead and include one here:
Draw a line from A to O, and draw a line from B to O. If these two lines form an angle of 45 degrees, then we have a regular octagon, since the triangle is isosceles, and a regular octagon can be constructed out of 8 isosceles triangles with angles of 67.5-67.5-45. The question is, is that angle 45 degrees?
If we let the distance from A to M be 1, then the distance from M to N is 1, and the distance from N to O (which is just the distance from A to N) is sqrt(2). So the distance from M to O is 1+sqrt(2). So whatever the angle between the A-O line and the M-O line, the tangent of that angle must be 1/(1+sqrt(2)).
Now we can use the half-angle identities that so many students forget (and that I, to be honest, needed to look up): sin(x/2)=sqrt((1-cos(x))/2), and cos(x/2)=sqrt((1+cos(x))/2), so tan(x/2)=sqrt((1-cos(x))/(1+cos(x))), or tan(x/2)=sqrt(1-cos(x)^2)/(1+cos(x)), which (since sin(x)^2+cos(x)^2=1) means tan(x/2)=sin(x)/(1+cos(x)). Taking x=45 degrees, we get tan(22.5)=(sqrt(2)/2)/(1+sqrt(2)/2), or 1/(1+sqrt(2)). This means the angle between A-O and M-O is 22.5 degrees, so by symmetry the angle between A-O and B-O is 45 degrees, and so we have a regular octagon.
On an unrelated note, it would be funny for someone with a Ness avatar to show up and say "no it isnt".

[@dylanlemon255]

MustardPipeLibrary lol

[@legendddx16]

jhatu

[@onimichaeloluwasegun7731]

Thank you sir