A circular lawn with a radius of 5 meters is surrounded by a circular walkway that is 4 meters wide. What is the area of the walkway?
To figure out the area of the walkway I found the difference between of the larger circle (circular lawn + circular walkway). To find the radius of the bigger circle I added the diameter of both the circular walkway and the circular lawn and divided by 2. (10+4)/2. I found the radius of the circle to be 7. So area of the bigger circle would be (7)squared times pi.
The Manhattan guide explains that the area of the bigger circle is 9(squared) times pie. Why is the radius of the bigger circle 9? I understand that the radius of the smaller circle is 5 but wouldn't the radius of the circular walkway be 2 since the entire walkway is 4 meters wide?
Please help!
Jose