document.write( "Question 1065504: An ellipse with center (4, 2) and focus (7, 2) is tangent to the y-axis. Find the length of the minor axis. \n" ); document.write( "
Algebra.Com's Answer #680743 by KMST(5328)\"\" \"About 
You can put this solution on YOUR website!
The major axis,
\n" ); document.write( "containing center (4,2) and focus (7,2),
\n" ); document.write( "is part of line \"y=2\" .
\n" ); document.write( "The focal distance is the distance between center and focus,
\n" ); document.write( "\"c=7-4=3\" .
\n" ); document.write( "There is another focus on the major axis,
\n" ); document.write( "with \"system%28x=4-3=1%2Cy=2%29\" .
\n" ); document.write( "The ellipse looks like this:
\n" ); document.write( " It is tangent to the y-axis
\n" ); document.write( "at vertex (0,2) ,
\n" ); document.write( "because an ellipse with a horizontal major axis
\n" ); document.write( "can only be tangent to a vertical line at a vertex.
\n" ); document.write( "So,the semi-major axis length is
\n" ); document.write( "the distance from that vertex to the center,
\n" ); document.write( "\"a=4-0=4\" .
\n" ); document.write( "Ŵe know that the length of the semi-minor axis, \"b\" ,
\n" ); document.write( "is related to \"a\" and \"c\" by
\n" ); document.write( "\"b%5E2%2Bc%5E2=A%5E2\" .
\n" ); document.write( "So, \"b%5E2%2B3%5E2=4%5E2\"
\n" ); document.write( "\"b%5E2%2B9=16\"
\n" ); document.write( "\"b%5E2=16-9\"
\n" ); document.write( "\"b%5E2=7\"
\n" ); document.write( "\"b=sqrt%287%29\" .
\n" ); document.write( "So, the length of the minor axis is
\n" ); document.write( "\"highlight%282sqrt%287%29%29\" .
\n" ); document.write( "
\n" );