document.write( "Question 897347: There are two concentric circles, whose areas are in the ratio 0.25. Determine the center if a straight line drawn from the center intersects the smaller and bigger circles at (2, 3) and (4, 8) respectively. \r
\n" ); document.write( "\n" ); document.write( "My answer is (0, -2). Am I correct? Please show me the working.
\n" ); document.write( "

Algebra.Com's Answer #544088 by reviewermath(1029)\"\" \"About 
You can put this solution on YOUR website!
Q:
\n" ); document.write( "There are two concentric circles, whose areas are in the ratio 0.25. Determine the center if a straight line drawn from the center intersects the smaller and bigger circles at (2, 3) and (4, 8) respectively.
\n" ); document.write( "My answer is (0, -2). Am I correct? Please show me the working.
\n" ); document.write( "A:
\n" ); document.write( "If (h,k) is the center of the circle, then the radius of the smaller circle is equal to \"sqrt%28%28h-2%29%5E2%2B%28k-3%29%5E2%29\" and the radius of the bigger circle is \"sqrt%28%28h-4%29%5E2%2B%28k-8%29%5E2%29\". The ratio of the area of the smaller circle to the area of the bigger circle is equal to
\n" ); document.write( "\"%28%28h-2%29%5E2%2B%28k-3%29%5E2%29%2F%28%28h-4%29%5E2%2B%28k-8%29%5E2%29\" = 0.25
\n" ); document.write( "\"%28%28h-2%29%5E2%2B%28k-3%29%5E2%29\" = 0.25\"%28%28h-4%29%5E2%2B%28k-8%29%5E2%29\"
\n" ); document.write( "Multiply both sides by 4 and expand.
\n" ); document.write( "\"4h%5E2-16h%2B4k%5E2-24k%2B52\" = \"h%5E2-8h%2Bk%5E2-16k%2B80\"
\n" ); document.write( "\"3h%5E2-8h%2B3k%5E2-8k-28+=+0\"
\n" ); document.write( "The equation of the straight line is y = 2.5x - 2 so k = 2.5h - 2
\n" ); document.write( "\"3h%5E2-8h%2B3%282.5h+-+2%29%5E2-8%282.5h+-+2%29-28+=+0\"
\n" ); document.write( "\"3h%5E2-8h%2B3%286.25h%5E2-10h%2B4%29-20h-12+=+0\"
\n" ); document.write( "\"3h%5E2-8h%2B18.75h%5E2-30h%2B12-20h-12+=+0\"
\n" ); document.write( "\"21.75h%5E2-58h+=+0\"
\n" ); document.write( "Multiply both sides by 4.
\n" ); document.write( "\"87h%5E2-232h+=+0\"
\n" ); document.write( "Divide both sides by 29
\n" ); document.write( "\"3h%5E2-8h+=+0\"
\n" ); document.write( "h(3h - 8) = 0
\n" ); document.write( "h = 0 or h = 8/3
\n" ); document.write( "Using the equation k = 2.5h - 2.
\n" ); document.write( "If h = 0, then k = -2.
\n" ); document.write( "If h = 8/3, then k = 14/3.
\n" ); document.write( "There are two possible answers.
\n" ); document.write( "They are (0, -2) or (8/3, 14/3).\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );