SOLUTION: A circle has equation given by x^2+ax+y^2+by+c = 0 Find the radius of the circle, giving your answer to 2 decimal places, when a = 26, b = -81 and c = 73.

Algebra ->  Circles -> SOLUTION: A circle has equation given by x^2+ax+y^2+by+c = 0 Find the radius of the circle, giving your answer to 2 decimal places, when a = 26, b = -81 and c = 73.      Log On


   

Question 982706: A circle has equation given by
x^2+ax+y^2+by+c = 0
Find the radius of the circle, giving your answer to 2 decimal places, when a = 26, b = -81 and c = 73.
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
x%5E2%2Bax%2By%5E2%2Bby%2Bc+=+0+
when a+=+26,+b+=+-81 and c+=+73, we have
x%5E2%2B26x%2By%5E2-81y%2B73+=+0+....complete squares
%28x%5E2%2B26x%2B_%29-_%2B%28y%5E2-81y%2B_%29-_%2B73+=+0+

%28x%2B13%29%5E2-169%2B%28y-81%2F2%29%5E2-6561%2F4%2B73+=+0+
%28x%2B13%29%5E2%2B%28y-81%2F2%29%5E2+=+0%2B169%2B6561%2F4-73+
%28x%2B13%29%5E2%2B%28y-81%2F2%29%5E2+=+96%2B6561%2F4+
%28x%2B13%29%5E2%2B%28y-81%2F2%29%5E2+=+384%2F4%2B6561%2F4+
%28x%2B13%29%5E2%2B%28y-81%2F2%29%5E2+=+6945%2F4+
%28x%2B13%29%5E2%2B%28y-81%2F2%29%5E2+=+1736.25+
=>r%5E2=1736.25+
=>r=sqrt%281736.25%29+
=>r=41.6683+
=>r=41.67+