SOLUTION: An arc of a circle is 3πm long, and it subtends an angle of 72° at the center of the circle. Find the radius of the circle.

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Question 1065019: An arc of a circle is 3πm long, and it subtends an angle of 72° at the center of the circle. Find the radius of the circle.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +C+ = the circumference of the circle
I can say:
+%28+3%2Api+%29+%2F+C+=+72+%2F+360+
Multiply both sides by +360a+
+1080%2Api+=+72C+
+C+=+15%2Api+
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The formula for cicumference is:
+C+=+2%2Api%2Ar+
+15%2Api+=+2%2Api%2Ar+
+r+=+15%2F2+
+r+=+7.5+ m
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