SOLUTION: A circular cobblestone walk that surrounds a round fountain extends 5 ft from the fountain. What is the area (to the nearest whole number) of the walk if the diameter of the founta

Algebra ->  Circles -> SOLUTION: A circular cobblestone walk that surrounds a round fountain extends 5 ft from the fountain. What is the area (to the nearest whole number) of the walk if the diameter of the founta      Log On


   

Question 298816: A circular cobblestone walk that surrounds a round fountain extends 5 ft from the fountain. What is the area (to the nearest whole number) of the walk if the diameter of the fountain is 12.5 ft?
Answer by Stitch(470) About Me  (Show Source):
You can put this solution on YOUR website!
Area of a circle = pi+%2A+r%5E2
To find the area of just the walk around the fountain, you need to find the total area of the larger cirlce and then subtract the area of the inner circular fountain.
Diameter of the inner circle = 12.5ft
The radius is half of the diameter, so the radius of the inner circle is 6.25ft
Area of the inner circle = pi+%2A+6.25%5E2+=+122.72ft%5E2
Now the radius of the larger circle is the 6.25ft + 5ft = 11.25ft
Area of the outter circle = pi+%2A+11.25%5E2+=+397.61ft%5E2
The surface are of just the walk = 397.61ft%5E2+-+122.72ft%5E2
The surface are of just the walk = highlight%28275ft%5E2%29