SOLUTION: The area of the circle is 81pi sq. cm. Find the arc length of this circle that subtends a central angle of pi/3.

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Question 1014342: The area of the circle is 81pi sq. cm. Find the arc length of this circle that subtends a central angle of pi/3.
Answer by ikleyn(52817) About Me  (Show Source):
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The area of the circle is 81pi sq. cm. Find the arc length of this circle that subtends a central angle of pi/3.
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1. To find the radius, use this equation

   S = pi%2Ar%5E2,   or
   
   81%2Api = pi%2Ar%5E2.

   Then you immediately get r = 9 m.


2. The arc length is 

   L = r%2Aalpha = 9%2A%28pi%2F3%29 = 9%2A%283.14%2F3%29 = 3%2A3.14 m.

   Calculate yourself 3*3.14.