Find the radius from a chord

I am seeing your frustration. Please let me help you.
C= cord
H=height (sagitta)
solution #1: square one half of c
now divide by H
then add the value of H
finally divide by 2
DONE!!!

solution #2: Square C
now divide that by 8 times H
now Divide H by two and add
that to the former number.

solution #3: square H
multiply this by 4
Add to this, C squared
now divide all that by 8 times H

I sure hope this is helpful to find the radius of an arc knowing the cord length and the distance from the middle of the cord to the top of the arc

Yes, it's really works dear.

Originally Posted by Unregistered

I am seeing your frustration. Please let me help you.
C= cord
H=height (sagitta)
solution #1: square one half of c
now divide by H
then add the value of H
finally divide by 2
DONE!!!

solution #2: Square C
now divide that by 8 times H
now Divide H by two and add
that to the former number.

solution #3: square H
multiply this by 4
Add to this, C squared
now divide all that by 8 times H

I sure hope this is helpful to find the radius of an arc knowing the cord length and the distance from the middle of the cord to the top of the arc

I just laid out formula #2 on the floor of my garage, and used a string to intersect my points. In my example C=27" & H=3". Using formula #2, the radius was 31-7/8" or 31.875. It crossed my points exactly. Thanks!

Ken

Any simple formulas?

Practically speaking, I'm trying to find the length of an inside wall curve around an inside room corner. The over all corner angle (past the curved part) could be 90 degree, could be 45, or something else.

Yes, I could just measure it. But sometimes that's a bit difficult for one reason or another.

Thanks

Originally Posted by Unregistered

Yes that is correct. I know the lenght of the chord (c) and the height of the arc created by the chord (m). Is there a formula to find the radius with this information?

Could you please let me know what the formula is by e mail.
[.. guest link removed ..]

[Mrs X]

Bumping for unregistered

I stumbled on this through a google search. I was also looking for the same formula which I couldnt find in any of my study books. It's in the machinist handbook but I dont have one here at home.

Here's the Formula R = ((C/2)² + H²)/2H

So in your case with a chord of 30m and a height of 10m

R = ((30/2)² + 10²)/2*10
R = ((225+100)/20
R = 325/20
R = 16.25m

I know I'm a little late on the thread but should help others.

Thank-you, this was really useful and I have not had any joy finding this formula elsewhere. HH.

After using your equation to find my arc I found a slight error.
Maybe this will suffice.


radius = (m² + 1/4c)²
-----------
2m

By having only two measurments, first the length of the chord and the height of the curve, what is the formula for finding the radius of the circle