document.write( "Question 1068273: Find an equation(s) of the circle(s) of radius 4 with center on the line 4x + 3y + 7 = 0 and tangent to 3x + 4y + 34 = 0
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Algebra.Com's Answer #683504 by Fombitz(32388)![]() ![]() You can put this solution on YOUR website! Find the line perpendicular to the tangent line that goes through the circle center. \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "Perpendicular lines have slopes that are negative reciprocals. \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "Let the circle center be located at (h,k) and let the intersection point of the tangent line and the perpendicular line be (a,b). \n" ); document.write( ". \n" ); document.write( ". \n" ); document.write( ". \n" ); document.write( " ![]() \n" ); document.write( ". \n" ); document.write( "So you know that, \n" ); document.write( "1. \n" ); document.write( "2. \n" ); document.write( "The perpendicular line goes through both (h,k) and (a,b) so, \n" ); document.write( "3. \n" ); document.write( "and from the distance formula, \n" ); document.write( " \n" ); document.write( "4. \n" ); document.write( ". \n" ); document.write( ". \n" ); document.write( "Substitute 3 into 4, \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "First case, \n" ); document.write( " \n" ); document.write( "So then going back through the equations and substituting for h, \n" ); document.write( "5. \n" ); document.write( ". \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "6. \n" ); document.write( ". \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( "7. \n" ); document.write( "You have three equations, three unknowns, using Cramer's rule, \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "and then, \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "So the first circle is, \n" ); document.write( " \n" ); document.write( "and \n" ); document.write( "Second case, \n" ); document.write( " \n" ); document.write( "Again substituting as needed for h, \n" ); document.write( "8. \n" ); document.write( ". \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "9. \n" ); document.write( ". \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( "10. \n" ); document.write( "Again you have three equations, three unknowns, using Cramer's rule, \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "and then, \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "So the second circle is, \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( ". \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " |