document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1013457>Question 1013457</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a parabolic arch has a width of 18 m across the bottom. at a vertical distance 3 m above the bottom, the width across the arch is 12 m. what is the height of the arch in meters? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #629784 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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/cgi-bin/show-face.mpl?user=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=629784\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a parabolic arch has a width of 18 m across the bottom. at a vertical distance 3 m above the bottom, the width across the arch is 12 m. what is the height of the arch in meters?<BR>\n" );
document.write( "============<BR>\n" );
document.write( "Plot the points (-9,0) and (9,0) for the bottom.<BR>\n" );
document.write( "2 other points are (-6,3) and (6,3)<BR>\n" );
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document.write( "The form is y = -ax^2 + c<BR>\n" );
document.write( "0 = -a*81 + c<BR>\n" );
document.write( "3 = -a*36 + c<BR>\n" );
document.write( "----------------- Subtract<BR>\n" );
document.write( "-3 = -45a<BR>\n" );
document.write( "a = 1/15<BR>\n" );
document.write( "=================<BR>\n" );
document.write( "0 = -81/15 + c<BR>\n" );
document.write( "c = 5.4<BR>\n" );
document.write( "===============<BR>\n" );
document.write( "--> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+-x%5E2%2F15+%2B+5.4 ALIGN=MIDDLE  ALT=\"y+=+-x%5E2%2F15+%2B+5.4\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Height of the arch at the center = 5.4 meters </SPAN>\n" );
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