document.write( "Question 486044: Find an equation for a circle satisfying the given conditions:
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\n" ); document.write( "I need to know HOW to get this answer... I can get all the way to achieving the first aspect of the answer, but I can't seem to get the answer 169... I end up with 26?
\n" ); document.write( "Thank you in advance to anyone who can help. \n" ); document.write( "
Algebra.Com's Answer #332326 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "First we plot the two points:\r\n" );
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document.write( "Then we draw the diameter:\r\n" );
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document.write( "The midpoint of any diameter is the center of the circle, so\r\n" );
document.write( "we use the midpoint formula:\r\n" );
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document.write( "\"Midpoint+=+%28matrix%281%2C3%2C+++++4%2F2%2C+%22%2C%22+%2C+2%2F2%29%29+\"\r\n" );
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document.write( "\"Midpoint+=+%28matrix%281%2C3%2C+++++2+%2C+%22%2C%22%2C+1%29%29\"\r\n" );
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document.write( "So the center is the point (2,1)\r\n" );
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document.write( "So we plot it and label it:\r\n" );
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document.write( "Next we find the radius which is the distance from the center (2,1).\r\n" );
document.write( "to either end of the diameter, say (7,13). We use the distance formula:\r\n" );
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document.write( "\"distance+=+sqrt%28%28x%5B2%5D-x%5B1%5D%29%5E2%2B%28y%5B2%5D-y%5B1%5D%29%5E2%29\"\r\n" );
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document.write( "\"distance+=+sqrt%28%287-2%29%5E2%2B%2813-1%29%5E2%29\"\r\n" );
document.write( "\"distance+=+sqrt%285%5E2%2B12%5E2%29\"\r\n" );
document.write( "\"distance+=+sqrt%2825%2B144%29\"\r\n" );
document.write( "\"distance+=+sqrt%28169%29\"\r\n" );
document.write( "\"distance+=+13\"\r\n" );
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document.write( "So the radius is 13.\r\n" );
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document.write( "The standard equation for a circle is\r\n" );
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document.write( "(x - h)² + (y - k)² = r²\r\n" );
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document.write( "where the center is (h,k) and the centter is r.\r\n" );
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document.write( "So wh have (h,k) = (2,1), so h=2, k=1, and r=13.\r\n" );
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document.write( "Substituting, we have:\r\n" );
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document.write( "(x - 2)² + (y - 1)² = 13²\r\n" );
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document.write( "(x - 2)² + (y - 1)² = 169\r\n" );
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document.write( "Edwin
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