document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=43167>Question 43167</A>: <I><SPAN STYLE=\"word-break: break-all;\"> An oil tanker and a cruise ship leave port at the same time and travel straight-line courses at 10 mi/h and 25 mi/h, respectively. Two hours later they are 40 mi apart. What is the angle between their courses? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #28310 by </B><A HREF=/tutors/aboutme.mpl?userid=fractalier><B>fractalier(6550)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=fractalier><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=fractalier><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=28310\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If you draw the triangle diagram, you get a triangle with sides 20, 50 and 40 miles...now use the law of cosines...<BR>\n" );
document.write( "c^2 = a^2 + b^2 - 2ab cos C<BR>\n" );
document.write( "40^2 = 20^2 + 50^2 - 2(20)(50) cos C<BR>\n" );
document.write( "1600 = 400 + 2500 - 2000 cos C<BR>\n" );
document.write( "so that<BR>\n" );
document.write( "cos C = .65<BR>\n" );
document.write( "and<BR>\n" );
document.write( "C = 49.46 degrees </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );