document.write( "Question 771465: what is the radius of the circle x^2+y^2-2x-4y-31=0. \n" ); document.write( "

Algebra.Com's Answer #470249 by Cromlix(4381) $\"\"$ $\"About$

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The general equation of a circle
\n" ); document.write( "= x^2 + y^2 + 2gx + 2fy + c = 0
\n" ); document.write( "Centre = (-g,-f)
\n" ); document.write( "Therefore the equation of the circle:
\n" ); document.write( "x^2 + y^2 - 2x - 4y - 31 = 0
\n" ); document.write( "has (1,2) as the coordinates of its centre.
\n" ); document.write( "The radius is found from the equation:
\n" ); document.write( "square root of(g^2 + f^2 - c)
\n" ); document.write( "square root of(1^2 + 2^2 -(-31))
\n" ); document.write( "square root of(1 + 4 + 31)
\n" ); document.write( "square root of (36)
\n" ); document.write( "= 6 units.
\n" ); document.write( "Hope this helps.
\n" ); document.write( ":-) \n" ); document.write( "

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