# 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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