Derive Circumference of a Circle

Discussion in 'Other Pre-University Math' started by nycmathguy, Jul 7, 2022.

  1. nycmathguy

    nycmathguy

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    Derive the formulas C = d•pi and C = 2r•pi.
     
    nycmathguy, Jul 7, 2022
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  2. nycmathguy

    MathLover1

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    by the definition of pi (π) is the circumference c of any circle divided by its diameter d

    Put as an equation, pi is defined as π=c/d
    Rearranging this to solve for c we get c=π*d

    The diameter of a circle is twice its radius, so substituting 2r for d
    c=2π*r
     
    MathLover1, Jul 7, 2022
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  3. nycmathguy

    nycmathguy

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    Is that all it takes to derive the circumference of a circle?
     
    nycmathguy, Jul 7, 2022
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  4. nycmathguy

    MathLover1

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    yes
     
    MathLover1, Jul 7, 2022
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  5. nycmathguy

    nycmathguy

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    Ok. No picture of a circle needed???
     
    nycmathguy, Jul 7, 2022
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