document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1074312>Question 1074312</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If y varies directly as d find the constant of variation in the proportion 4/v=2/d\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #689003 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=689003\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> y = kd\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "this means y varies directly with d.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "equation is 4/y = 2/d\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "cross multiply to get 2y = 4d\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "divide both sides by 2 to get y = 2d\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "constant of variation is 2.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "what this says is that d is always 2 times the value of y.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "to confirm, start with your original equation of 4/y = 2/d\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "choose a value of d at random.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "i chose 556.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "since y = 2d, then y must be equal to 1112\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "your equation of 4/y = 2/d becomes 4/1112 = 2/556\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "simplify both to get 1/278 = 1/278\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "you can choose any number for d, and you will find that y will have to be 2 times that for the equation to be true.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "another example:\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "start with 4/y = 2/d\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "let d = 4\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "equation becomes 4/y = 2/4\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "multiply both sides by y and multiply both sides by 4 to get 16 = 2y\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "divide both sides by 2 to get y = 8\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "8 is w times the value of 4.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "this will always happen when y = 2d.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "direct variation form is y = kd.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "k is the constant of variation which is equal to 2.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );