document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=857177>Question 857177</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I am trying to work out the area that my fish finder is covering at different depths under my boat. The angle it sends the beam down is 55 degrees. My question is at 10, 20, 30 40 metres what is the diameter of the circle.<BR>\n" );
document.write( "Regards Chris  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #516408 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=516408\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I am trying to work out the area that my fish finder is covering at different depths under my boat. The angle it sends the beam down is 55 degrees. My question is at 10, 20, 30 40 metres what is the diameter of the circle.<BR>\n" );
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document.write( "55 degs is the included angle, --> 27.5 degs either side of center.<BR>\n" );
document.write( "The radius (on the bottom) over the depth = tan(27.5)<BR>\n" );
document.write( "r = d*tan(27.5) meters<BR>\n" );
document.write( "r = 10*tan(27.5) =~ 5.2 meters<BR>\n" );
document.write( "etc<BR>\n" );
document.write( "radius =~ 1/2 the depth<BR>\n" );
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