document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=759712>Question 759712</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A reflecting telescope has a parabolic mirror for which the distance from the vertex to the focus is 26 feet. If the distance across the top of the mirror is 76 inches, how deep is the mirror in the center? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #462184 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=462184\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A reflecting telescope has a parabolic mirror for which the distance from the vertex to the focus is 26 feet. If the distance across the top of the mirror is 76 inches, how deep is the mirror in the center?<BR>\n" );
document.write( "***<BR>\n" );
document.write( "place vertex at (0,0)<BR>\n" );
document.write( "parabolic mirror opens upward:<BR>\n" );
document.write( "equation of parabola: x^2=4py<BR>\n" );
document.write( "p=26*12=312 inches<BR>\n" );
document.write( "4p=1248<BR>\n" );
document.write( "coordinates of right edge of mirror: (38,y)<BR>\n" );
document.write( "x^2=4py<BR>\n" );
document.write( "38^2=1248y<BR>\n" );
document.write( "y=1444/1248&#8776;1.1571<BR>\n" );
document.write( "how deep is the mirror in the center? 1.1571 inches </SPAN>\n" );
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