document.write( "Question 992326: Please help me with this! Show that the two circles (x - 3)^2 + (y-4)^2 = 25 and (x-1)^2 + (y-5/2)^2 =225/4. touch each other. \n" ); document.write( "
Algebra.Com's Answer #611975 by Theo(13342)![]() ![]() You can put this solution on YOUR website! the two circles are: \n" ); document.write( "(x-3)^2 + (y-4)^2 = 25 \n" ); document.write( "(x-1)^2 + (y-5/2)^2 = 225/4\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if they touch, then the tangent line to each circle will pass through the point that they touch at.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the radius of each circle will be perpendicular to the tangent line at that point.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this means the two radii will form a straight line that goes through the point of tangency and will intersect both circles at the point of tangency.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the line will be a straight line formed by the line segment between the two centers of the cirfcle.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the centers of each circle are (3,4) and (1,(5/2)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "using these two points, you get a straight line with the equation of y = 3/4 * x + 7/4.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "that line should intereset with both circles at the same point.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i solved it graphically to see that the point of intersection is (7,7).\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "that graph is shown below:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " ![]() \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "it should be able to be solved algebraically but i didn't do it because i ran out of time and it's messy.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i did verify algebraically that the point (7,7) satisfies both equations, so there's no question that is the point of intersection of the two circles.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you would probably want to solve the intersection of that line with each equation using the substitution method.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "graphing was much easier.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |