document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=775651>Question 775651</A>: <I><SPAN STYLE=\"word-break: break-all;\"> An aeroplane can fly at 250km\h in still air. How long will it take it to reach a place 500 km to the south-west if a wind is blowing at 80k<BR>\n" );
document.write( "m\h from west<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #473059 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=473059\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> An aeroplane can fly at 250km\h in still air. How long will it take it to reach a place 500 km to the south-west if a wind is blowing at 80k<BR>\n" );
document.write( "m\h from west<BR>\n" );
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document.write( "A heading adjustment is needed into the wind to give a ground track of 225 (southwest).<BR>\n" );
document.write( "The angle between the wind direction and groundtrack is 135 degs.<BR>\n" );
document.write( "Use the Law of Sines to find the heading correction.<BR>\n" );
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document.write( "250/sin(135) = 80/sin(A)<BR>\n" );
document.write( "sin(A) = 80*sin(135)/250<BR>\n" );
document.write( "A = 13.0778 degs --> 13 degs<BR>\n" );
document.write( "The 3rd angle, B = 180 - (A + 135)<BR>\n" );
document.write( "B = 32 degs<BR>\n" );
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document.write( "Use the Law of Sines again to find AC, the groundspeed<BR>\n" );
document.write( "250/sin(135) = AC/sin(32)<BR>\n" );
document.write( "AC = 186.95 km/hr (the plane's groundspeed on a track of 225 degs)<BR>\n" );
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document.write( "500/AC =~ 2.67 hours<BR>\n" );
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