document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1141230>Question 1141230</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A certain hill is represented by a hemisphere of radium 1km. A man 180cm tall walks down the hill from the summit S at 6km/h. How long (correct to the nearest second) will it be before he is invisible to a person lying on the ground at S </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #761917 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=761917\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A certain hill is represented by a hemisphere of radium 1km.<BR>\n" );
document.write( " A man 180cm tall walks down the hill from the summit S at 6km/h. How long (correct to the nearest second) will it be before he is invisible to a person lying on the ground at S<BR>\n" );
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document.write( "S is at the summit of the hill which is the very top of the hemisphere <BR>\n" );
document.write( "Draw a horizontal line thru the this point<BR>\n" );
document.write( "Change 1 km to 1000 meters<BR>\n" );
document.write( "Change 180 cm to 1.8 meters<BR>\n" );
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document.write( "the man's highest point is 1.8 + 1000 = 1001.8 meters from the center<BR>\n" );
document.write( "A right triangle is formed point C to the center A, and a point on the horizontal line that is 1001.8 meters from the center (the man highest point)<BR>\n" );
document.write( "find the angle at the center using the cosine<BR>\n" );
document.write( "cos(A) = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1000%2F1001.8 ALIGN=MIDDLE  ALT=\"1000%2F1001.8\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "A = 3.435 degrees<BR>\n" );
document.write( "Find the portion of the circumference that the man walks on the hemisphere.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3.435%2F180 ALIGN=MIDDLE  ALT=\"3.435%2F180\"   DISABLED_style= \"max-width:90%; height:auto;\" > * <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=pi%2A1000 ALIGN=MIDDLE  ALT=\"pi%2A1000\"   DISABLED_style= \"max-width:90%; height:auto;\" > ~ 60 meters<BR>\n" );
document.write( "Find the time it takes to walk this distance at 6 km/hr in seconds<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=6000%2F3600 ALIGN=MIDDLE  ALT=\"6000%2F3600\"   DISABLED_style= \"max-width:90%; height:auto;\" > * 60 = 100 seconds\r<BR>\n" );
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document.write( " </SPAN>\n" );
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