TIP: Easy Arc Radius (Intersecting Chords Theorem)

Simple tip to find the arc radius of a circle from just a small piece of arc segment. We will be using the intersecting chords theorem to find the radius and diameter given any portion of the circle that we can measure the length and height of. When no other method will work this method always will.

== Check us out at ==

== Help support the show ==

[chessmith]

GREAT JOB! I'm a retired carpenter still playing with wood- I recentlyI had to make a bird feeder from the remains of the original-the individual wanted it to match as close as possible. It Had a partial arc on a piece which appeared to be smooth, so I needed to figure the radius- so glad I found your explanation- you are a teacher that would have made a difference when i was coming along. Thank you for sharing your gift!

[cw]

I struggled for the better part of an hour trying to figure out how to calculate radius of a circle using chord. This video allowed me to comprehend and calculate in 6 minutes. Thank you!

[dresdenkiller]

Learnt something more valuable than 10 TED talks put together. Thanks!

[workshoponwheels]

Thumbs up for using metric! And still stating the imperial system for those who prefer that. Now I realize why I should have been awake during math classes!

[donttellthekids]

Have been a finish carpenter for almost 50 years and was "allowed" to skip Geometry in 10th grade to go immediately in Algebra regretted it ever since....Thank for your very articulate explanation!

[eibhlinniccolla]

It's 1 in the morning, and for some reason this problem popped into my head, in the context of drawing curves in sewing patterns from a sketch. Thank you for a concise and informative video.

[seanwolfe]

Thank God for you! I found the formula on a machinist website….WAY more convoluted. This was simple to follow & easy to remember. Thank you!

[rogerdrum]

I make templates of existing arch top door frames to build custom doors. I always outline the old doors and usually that works. However, using this video I will be able to do this formula and get close and then trim my doors to fit. It’ll save time and materials. Thanks a ton for sharing.

[TK]

Brilliantly explained. I've been trying to build wheel arch on a car but needed to know diameter of the circle that forms the arch (chord) so I can cut out steel at correct diameter. Now I know 👍👏

[mramirez]

I've been watching your videos for a while now. And love what you do. I was helping my daughter with some math homework and low and behold this came in real handy!!!! Thanks for great videos and explanations!!!!

[MemeBiologist]

thank you. i needed this to find out how big my radius needed to be to trace a circle on sound deadening material 💯

[rickl]

Thanks for posting, this was exactly what I was looking for. 😊

[miguelverdial]

Amazing! Great explanation, I was looking for this for 2 days....

[garlicdoggo]

amazing trick and amazing explanation, you're an absolute lifesaver

[imaginationingrained]

Thanks!! I’ve been searching the internet for this exact equation to solve for a very similar issue, and I’ve watched about 15 videos before I found this. I knew it was a simple solution, but because I never took geometry in high school, it was a little over my head until I found this. So, thanks again!!

[survival_man]

Awesome explanation, thank you a lot. I have known website that did all the work for me but knowing the real reason behind why it works I know feel smarter and able to work faster and with less help !

[Mitermikeswoodshop]

i loved geometry in school. thanks for the trip down memory lane....Ray nice explanation for those who don't understand.

[georgemoua]

I knew there was a way to do this. I knew somewhere in time I had learned about this in high school. Thanks for the help.

[danielcharron]

Thanks for the formula. I was looking to find the radius with only an arc and chord and no centre of circle. This is exactly what I needed.
P.S. The metric system is better to deal with. They did a survey and found out that 4 out of 3 people are bad at fractions. (Joke)😄

[garrylove]

You're a genius. Thank you! I can finish my project now