document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=600886>Question 600886</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A plane is flying at an altitude of about 7 miles above Earth. What is the measure of the arc that represents the part of Earth you can see? The radius of Earth is about 4000 miles.   Please help me. I have tried to do this problem many times but the concept confuses me. Thank you.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #379544 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=379544\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A plane is flying at an altitude of about 7 miles above Earth. What is the measure of the arc that represents the part of Earth you can see? The radius of Earth is about 4000 miles. <BR>\n" );
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document.write( "The plane's distance from the Earth's center is 4007 miles.<BR>\n" );
document.write( "The distance on the surface of Earth is 4000 miles.<BR>\n" );
document.write( "The distance from the plane to the horizon is the 3rd leg of a right triangle.<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d+=+sqrt%284007%5E2+-+4000%5E2%29 ALIGN=MIDDLE  ALT=\"d+=+sqrt%284007%5E2+-+4000%5E2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "d =~ 236.75 miles<BR>\n" );
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document.write( "The arc on the surface is close to that.<BR>\n" );
document.write( "The angle A at Earth's center = arccos(4000/4007) =~ 3.3872 degs<BR>\n" );
document.write( "The arc is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2%2Api%2Ar%2A%28A%2F360%29 ALIGN=MIDDLE  ALT=\"2%2Api%2Ar%2A%28A%2F360%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "=~ 236.47 miles each direction<BR>\n" );
document.write( "x2 --> 472.94 miles<BR>\n" );
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