document.write( "Question 1142957: Find the equation of the circle. The circle passes through the points (-4,8) (4,-4) and (3,-9) \n" ); document.write( "

Algebra.Com's Answer #763694 by Alan3354(69443) $\"\"$ $\"About$

You can put this solution on YOUR website!
Find the equation of the circle. The circle passes through the points A(-4,8), B(4,-4) and C(3,-9)
\n" ); document.write( "------------------
\n" ); document.write( "1 way to do this:
\n" ); document.write( "Label the points.
\n" ); document.write( "Find the perpendicular bisectors of AB and BC.
\n" ); document.write( "The intersection of the bisectors is the center, (h,k).
\n" ); document.write( "The distance from the center to any point is the radius, r.
\n" ); document.write( " $\"%28x-h%29%5E2+%2B+%28y-k%29%5E2+=+r%5E2\"$
\n" ); document.write( "=======================
\n" ); document.write( "Another way:
\n" ); document.write( "

\r\n" );
document.write( "\r\n" );
document.write( "| x    y    x^+y^2    1|\r\n" );
document.write( "|-4    8      80      1|\r\n" );
document.write( "| 4   -4      32      1| = 0\r\n" );
document.write( "| 3   -9      90      1|\r\n" );
document.write( "\r\n" );
document.write( "

\n" ); document.write( "=========================
\n" ); document.write( "The 2nd method may not be convenient, but I have an Excel sheet that does the work.
\n" ); document.write( "Also for parabolas, and for any conic.
\n" ); document.write( " \n" ); document.write( "

\n" );