Question 169634
A circular pool is 46 feet in diameter and has a flag stone walk around it that is 4 feet wide. Find the area of the walk. Express the answer in terms of pie.
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Adding 4 ft to both sides gives an outside diameter of the walk of 54 ft.
The area of the walk is the area of a 54 ft dia circle minus the area of the pool.
Using the radii is simpler, they're 27 ft and 23 ft.  So it's
pi*27^2 - pi*23^2
= 729pi - 529pi
= 200*pi sq ft.
BTW, it's pi, the Greek letter, not pie.