sandy wrote:

The area of circle W is 16π and the area of circle Z is 4π. What is the ratio of the circumference of W to the circumference of Z ?

A. 2 to 1

B. 4 to 1

C. 8 to 1

D. 16 to 1

E. 32 to 1

Practice Questions

Question: 10

Page: 151

Area of circle = πr²Area of circle W is 16πWe can write:

16π = πr²

Divide both sides by π to get: 16 = r²

Solve: r = 4 or r = -4

Since the radius can't be negative, we know that

the radius of circle W is 4Area of circle Z is 4πWe can write:

4π = πr²

Divide both sides by π to get: 4 = r²

Solve: r = 2 or r = -2

Since the radius can't be negative, we know that

the radius of circle Z is 2What is the ratio of the circumference of W to the circumference of Z ?Circumference of circle = 2πrSo, the circumference of circle W = (2)(π)(

4) =

8πThe circumference of circle Z = (2)(π)(

2) =

4πRatio =

8π/

4π = 2/1 = 2 to 1

Answer: A

Cheers,

Brent

_________________

Brent Hanneson – Creator of greenlighttestprep.com

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