document.write( "Question 480006: the circle passes through the points (0, 0), (O, 5), (3, 3). Find the equation of the circle. \n" ); document.write( "
Algebra.Com's Answer #328833 by lwsshak3(11628)![]() ![]() ![]() You can put this solution on YOUR website! The circle passes through the points (0, 0), (O, 5), (3, 3). Find the equation of the circle. \n" ); document.write( "** \n" ); document.write( "Standard form of equation for circle: (x-h)^2+(y-k)^2=r^2, (h,k) being the center of the circle with radius=r. \n" ); document.write( ".. \n" ); document.write( "3 equations from coordinates of given 3 points (0, 0), (0, 5), (3,3) \n" ); document.write( "1) (0-h)^2+(0-k)^2=r^2 \n" ); document.write( "2) (0-h)^2+(5-k)^2=r^2 \n" ); document.write( "3) (3-h)^2+(3-k)^2=r^2 \n" ); document.write( ".. \n" ); document.write( "solving for k \n" ); document.write( "1) (0-h)^2+(0-k)^2=r^2 \n" ); document.write( "2) (0-h)^2+(5-k)^2=r^2 \n" ); document.write( "subtract eq2 fm eq1 \n" ); document.write( "k^2-(5-k)^2=0 \n" ); document.write( "k^2-(25-10k+k^2)=0 \n" ); document.write( "k^2-25+10k-k^2=0 \n" ); document.write( "25-10k=0 \n" ); document.write( "10k=25 \n" ); document.write( "k=2.5 or 5/2 \n" ); document.write( ".. \n" ); document.write( "solving for h \n" ); document.write( "2) (0-h)^2+(5-k)^2=r^2 \n" ); document.write( "3) (3-h)^2+(3-k)^2=r^2 \n" ); document.write( "subtract eq3 fm eq2 \n" ); document.write( "h^2+(5-2.5)^2-[(3-h)^2+(3-2.5)^2]=0 \n" ); document.write( "h^2+(2.5)^2-[9-6h+h^2+.5^2]=0 \n" ); document.write( "h^2+6.25-9+6h-h^2-.25=0 \n" ); document.write( "6.25-9.25+6h=0 \n" ); document.write( "-3=-6h \n" ); document.write( "h=.5 or 1/2 \n" ); document.write( ".. \n" ); document.write( "solving for r \n" ); document.write( "1) (0-h)^2+(0-k)^2=r^2 \n" ); document.write( "(1/2)^2+(5/2)^2=r^2 \n" ); document.write( "1/4+25/4=r^2=26/4=13/2 \n" ); document.write( ".. \n" ); document.write( "Equation of circle: \n" ); document.write( "(x-1/2)^2+(y-5/2)^2=13/2 \n" ); document.write( "see graph below as visual check on answer \n" ); document.write( "note: a more precise algebriac check can be made by plugging in coordinates of given points into equation \n" ); document.write( ".. \n" ); document.write( "y=±(13/2-(x-.5)^2)^.5+2.5 \n" ); document.write( " |