Thread: Finding the Radius when all i have is the arc length

Im not sure if Trig is the right forum to post in, I apologize if I am in the wrong spot....
I have a project at work where I was given the arc lenght of a line and was asked to find the radius of the circle. What is the formula to do this....if it exists?
Thanks
Shante

Originally Posted by Shante

Im not sure if Trig is the right forum to post in, I apologize if I am in the wrong spot....
I have a project at work where I was given the arc lenght of a line and was asked to find the radius of the circle. What is the formula to do this....if it exists?
Thanks
Shante

is arclength

is the radius

is the sector angle in radians

The radius can be found as follows



Where L is the arc length and is the angle corresponding to the arc length.

I know i sound like a total novice here, I promise im not, its just been forever since i have even thought about this type of math.....I dont have the angle....is there a way for me to find that....all they told me is they want a 60" arc length but gave me no other information....and in order to bend the piece of metal to that arc length they need the radius....sorry!

Hmm... you need at least two pieces of information to work with. An arc of a given length x (60" in your case) could be any radius, depending on the ange. the smaller the radius. the greater the angle.

Might you know what portion of a circle you need to bend the metal to? Half a circle? A quarter circle? A definition along those lines would give an angle and thus, allow a radius to be calculated.

All they have given me at this point is the arc length, I kept trying to tell them I didnt think that was enough information. I appreciate the help

Thanks