SOLUTION: Could you please show me how to solve this questions? I need to learn how to do it, I need to see how can I get the answer. I have the formulas but for some reason, I never get th

Algebra ->  Geometry-proofs -> SOLUTION: Could you please show me how to solve this questions? I need to learn how to do it, I need to see how can I get the answer. I have the formulas but for some reason, I never get th      Log On


   

Question 446745: Could you please show me how to solve this questions? I need to learn how to do it, I need to see how can I get the answer. I have the formulas but for some reason, I never get the correct answer and it is frustrating for me. I hope you can help me. Thank you.
20: Find the radius of a circle with circumference 4 sqrt(3)(pi).
21: Find the radius of a circle with area (4/9) (pi).
22: What is the circumference of a circle with area 49(pi)?
Answer by katealdridge(100) About Me  (Show Source):
You can put this solution on YOUR website!
The circumference is the diameter times pi. The diameter is twice the radius. If the circumference is 4sqrt3pi, then the diameter is 4sqrt3. That makes the radius half the diameter-2sqrt3.
The area is the radius squared times pi. So if the area is 4/9pi, then the radius squared is 4/9. Then take the sqrt is 4/9 to get the radius. That's 2/3.
If the area is 49 pi, then the radius squared is 49. Then the radius is the sqrt of 49 which is 7. So the radius is 7. The circumference the twice the radius times pi. So the circumference is 14pi.