SOLUTION: 4x^2+4y^2= 81 determine the center and radius of the circle

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Question 260136: 4x^2+4y^2= 81
determine the center and radius of the circle
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Given:
4x%5E2%2B4y%5E2+=+81 determine the center and the radius.
Let's first get your equation into the standard form for a circle:
%28x-h%29%5E2%2B%28y-k%29%5E2+=+r%5E2 where the center is at (h, k) and the radius is r.
4x%5E2%2B4y%5E2+=+81 Divide both sides by 4.
x%5E2%2By%5E2+=+20.25 This is now in standard form, so h = 0, k = 0, and r%5E2+=+20.25 and r+=+4.5
The center is at (0, 0) and the radius is r = 4.5