document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=180794>Question 180794</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/9780470280768/algebrahomeworkh>Analytic Trigonometry</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> Standing on the bank of a river, a surveyor measures the angle to the top of a tree on the opposite bank to be 23 degrees.  He backs up 45ft and remeasures the angle to the top of the tree at 18 degrees.  How wide is the river? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #135527 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=135527\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Standing on the bank of a river, a surveyor measures the angle to the top of a tree on the opposite bank to be 23 degrees. He backs up 45ft and remeasures the angle to the top of the tree at 18 degrees. How wide is the river?<BR>\n" );
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document.write( "Let the width of the river be \"x\".<BR>\n" );
document.write( "Draw the picture and solve for \"x\".<BR>\n" );
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document.write( "tan(23) = tree/x<BR>\n" );
document.write( "tan(18) = tree/(x + 45)<BR>\n" );
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document.write( "tree = x*tan(23)<BR>\n" );
document.write( "tree = (x+45)*tan(18)<BR>\n" );
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document.write( "Equation:<BR>\n" );
document.write( "x*tan(23) - (x+45)*tan(18)\r<BR>\n" );
document.write( "\n" );
document.write( "xtan(23) - x*tan(18) = 45*tan(18)\r<BR>\n" );
document.write( "\n" );
document.write( "x[tan(23)-tan(18)] = 45*tan(18)\r<BR>\n" );
document.write( "\n" );
document.write( "Solve for \"x\"<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );