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  1. #1
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    Triangle Circle Diameter (2k3)

    This is half excel half math help. If i have 1 side of an equilateral triangle - what is the easiest formula to put into excel that will give me the diameter of the circle using the 3 end points of the resultant triangle?

    Thanks!
    <img src=/w3timages/blueline.gif width=33% height=2>
    <big>John</big>

  2. #2
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    Re: Triangle Circle Diameter (2k3)

    If you denote the side by s, a little elementary maths shows that the radius of the circle is s / (square root of 3), and the diameter is twice that: 2 * s / (square root of 3). So if you enter the side in cell A1, the formula

    =2*A1/SQRT(3)

    will return the diameter.

  3. #3
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    Re: Triangle Circle Diameter (2k3)

    If A1 has the length:

    =A1/COS(PI()/6)

    (pi/6 = 30

  4. #4
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    Re: Triangle Circle Diameter (2k3)

    I suppose even "easier" than both Hans and my equation is:

    =1.1547*A1

    if you are happy with 6 sig figs (the 1.1547 is actually 1.1547<font color=red>0</font color=red>, Of course you can simplify it further by reducing the sig figs accordingly(1.155*A1, 1.15*A1, 1.2*A1 or even just =A1 if you are happy with just 1 sig fig... <img src=/S/smile.gif border=0 alt=smile width=15 height=15>

    Steve

  5. #5
    Plutonium Lounger
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    Re: Triangle Circle Diameter (2k3)

    And here is a picture...

  6. #6
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    Re: Triangle Circle Diameter (2k3)

    Thanks Hans & Steve you've both made it clear as mud <img src=/S/laugh.gif border=0 alt=laugh width=15 height=15>

    just kidding, thanks!
    <img src=/w3timages/blueline.gif width=33% height=2>
    <big>John</big>

  7. #7
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    Re: Triangle Circle Diameter (2k3)

    Here is my picture for the solution

    Steve
    PS cos(30

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