document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1103698>Question 1103698</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I have a formula by Huebsher used in engineering duct design. It calculates the equivalent diameter of a round duct using length major (width) and length minor (height) of a rectangular duct. I need to solve this equation for the length major (width) of the rectangular duct because height and equivalent diameter of a round duct will be already known. The formula is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d=1.30%28ab%29%5E0.625+%2F%28a%2Bb%29%5E0.25 ALIGN=MIDDLE  ALT=\"d=1.30%28ab%29%5E0.625+%2F%28a%2Bb%29%5E0.25\"   DISABLED_style= \"max-width:90%; height:auto;\" > where d=round duct diameter, b=length minor (duct height) and a=length major (duct width) I need to solve for a (a=???) I am making an Excel calculator for my duct sizing and the formula is solved for the wrong variable for my use. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #718462 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=718462\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I have a formula by Huebsher used in engineering duct design. It calculates the equivalent diameter of a round duct using length major (width) and length minor (height) of a rectangular duct. I need to solve this equation for the length major (width) of the rectangular duct because height and equivalent diameter of a round duct will be already known. The formula is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d=1.30%28ab%29%5E0.625+%2F%28a%2Bb%29%5E0.25 ALIGN=MIDDLE  ALT=\"d=1.30%28ab%29%5E0.625+%2F%28a%2Bb%29%5E0.25\"   DISABLED_style= \"max-width:90%; height:auto;\" > where d=round duct diameter, b=length minor (duct height) and a=length major (duct width) I need to solve for a (a=???) <BR>\n" );
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document.write( "That's a mess.<BR>\n" );
document.write( "I would do it from scratch.<BR>\n" );
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document.write( "Area of rectangle = a*b<BR>\n" );
document.write( "Area of circle = pi*d^2/4<BR>\n" );
document.write( "For equal areas: a*b = pi*d^2/4<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a+=+pi%2Ad%5E2%2F%284b%29 ALIGN=MIDDLE  ALT=\"a+=+pi%2Ad%5E2%2F%284b%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "I looked up Huebner, and it apparently takes into account other factors besides area.<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d=1.30%28ab%29%5E0.625+%2F%28a%2Bb%29%5E0.25 ALIGN=MIDDLE  ALT=\"d=1.30%28ab%29%5E0.625+%2F%28a%2Bb%29%5E0.25\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d%5E4+=+1.3%5E4%28ab%29%5E2.5+%2F%28a%2Bb%29 ALIGN=MIDDLE  ALT=\"d%5E4+=+1.3%5E4%28ab%29%5E2.5+%2F%28a%2Bb%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d%5E4%2A%28a%2Bb%29+=+1.3%5E4%28ab%29%5E2.5 ALIGN=MIDDLE  ALT=\"d%5E4%2A%28a%2Bb%29+=+1.3%5E4%28ab%29%5E2.5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28d%5E4%2Aa+%2B+d%5E4%2Ab%29+=+1.3%5E4%2A%28a%5E2.5%2Ab%5E2.5%29 ALIGN=MIDDLE  ALT=\"%28d%5E4%2Aa+%2B+d%5E4%2Ab%29+=+1.3%5E4%2A%28a%5E2.5%2Ab%5E2.5%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a%2Ad%5E4+-+a%5E2.5%2A1.3%5E4%2Ab%5E2.5+-+b%2Ad%5E4+=+0 ALIGN=MIDDLE  ALT=\"a%2Ad%5E4+-+a%5E2.5%2A1.3%5E4%2Ab%5E2.5+-+b%2Ad%5E4+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "At this point I would try an Excel sheet.\r<BR>\n" );
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