SOLUTION: How do I find the circumference of a circle when I only know the area? I know the area is 64pi miles^2. How do I use that information to find the circumference? Also is

Algebra ->  Circles -> SOLUTION: How do I find the circumference of a circle when I only know the area? I know the area is 64pi miles^2. How do I use that information to find the circumference? Also is       Log On


   

Question 717014: How do I find the circumference of a circle when I only know the area?

I know the area is 64pi miles^2. How do I use that information to find the circumference?

Also is the 64 the radius or the diameter?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The formula for area is
+A+=+pi%2Ar%5E2+
You can solve this for radius
+r%5E2+=+A+%2F+pi+
+r+=+sqrt%28+A%2Fpi+%29+
You are given that
+A+=+64%2Api+, so
+r+=+sqrt%28+64%2Api+%2F+pi+%29+
+r+=+sqrt%28+64+%29+
+r+=+8+
---------
The formula for circumference is
+C+=+2%2Api%2Ar+
+C+=+2%2Api%2A8+
+C+=+16%2Api+ answer