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Math Help - Finding the Radius when all i have is the arc length

  1. #1
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    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
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  2. #2
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    Re: Finding the Radius when all i have is the arc length

    Quote Originally Posted by Shante View Post
    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
    s = r\theta

    s is arclength

    r is the radius

    \theta is the sector angle in radians
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  3. #3
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    Re: Finding the Radius when all i have is the arc length

    The radius can be found as follows

    r= \frac{180\times L}{\pi \times \theta}

    Where L is the arc length and \theta is the angle corresponding to the arc length.
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  4. #4
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    Re: Finding the Radius when all i have is 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!
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  5. #5
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    Re: Finding the Radius when all i have is the arc length

    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.
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  6. #6
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    Re: Finding the Radius when all i have is the arc length

    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
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