Geometry

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What is the circumference of the circle if the radius is:
5x-My answer was 57(x)pi.

What is the radius if the circumference is:
30x(pi)-My answer was 2x.
(x + y)pi -My answer (x+y)/7.
What is the length of the arc if:

radius=3 degree of measurement of arc=6- My answer was pi/9.
radius=4 degree of measurement of arc=7- My answer was 9(pi)/18.
radius=2 degree of measurement of arc=x- My answer was x(pi)/15.

My answers for these questions were incorrect. I am unsure of how to redo them.Cheers!

  • Geometry -

    1. circumf = 2πr
    = 2π(5x) = 10πx

    2. using the above ...
    30xπ = 2πr
    r = 30xπ/(2π) = 15x

    3. arclength = rØ , where Ø is the central angle in radians

    if r=3
    if arcangle =6° , then Ø = π/30

    (to change ° to radians, multipy your degree unit by π/180) ..... 6(π/180) = π/30

    so:
    arc = 3(π/30) = π/10

    The others in this third part of your post are done the same way

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