document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=980503>Question 980503</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If b is positive, what is the value of b in the geometric sequence 9,a,4,b? Express your answer as a common fraction.<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #601630 by </B><A HREF=/tutors/aboutme.mpl?userid=rothauserc><B>rothauserc(4718)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=rothauserc><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=rothauserc><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=601630\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> the nth element of a geometric series is<BR>\n" );
document.write( "a(n) = a(0)*r^(n-1) where a(0) is the first element, r is the common ratio<BR>\n" );
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document.write( "we are given 9,a,4,b and asked to find b<BR>\n" );
document.write( "4 = 9*r^2<BR>\n" );
document.write( "r^2 = 4 / 9<BR>\n" );
document.write( "r = 2 / 3<BR>\n" );
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document.write( "b = 9*(2/3)^3<BR>\n" );
document.write( "b = 9*(8/27)<BR>\n" );
document.write( "b = 8/3<BR>\n" );
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