document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1185764>Question 1185764</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A railroad bridge is built over a V-shaped canyon. If the supports are 3 feet long at each end, the center support is 563 feet long, and the supports increase in length by 4 feet with each support (from 3 feet to 563 feet), what is the total length of all the supports? Please show the work, 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 #816603 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13203)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=816603\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "The sum of the lengths of the supports is<br><BR>\n" );
document.write( "3+7+11+...+559+563+559+...+11+7+3<br><BR>\n" );
document.write( "= 2(3+7+11+...+559)+563<br><BR>\n" );
document.write( "Find the sum of the arithmetic sequence in parentheses using<BR>\n" );
document.write( "sum = number of terms times average of all the terms, or<BR>\n" );
document.write( "sum = number of terms times average of first and last terms.<br><BR>\n" );
document.write( "The number of terms is (last minus first) divided by common difference, plus 1.<br><BR>\n" );
document.write( "(559-3)/4+1 = 139+1 = 140<br><BR>\n" );
document.write( "The average of the first and last terms is (3+559)/2 = 281.<br><BR>\n" );
document.write( "The sum of the lengths of the supports is then<br><BR>\n" );
document.write( "2(140*281)+563<br><BR>\n" );
document.write( "Use a calculator to get<br><BR>\n" );
document.write( "ANSWER: 79,243 feet<br><BR>\n" );
document.write( " </SPAN>\n" );
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