document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1138627>Question 1138627</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I can not figure out what in trapezoid WXYZ with bases ZY and WX, ZY= 12, YX= 10, WZ= 17, and ZD= 8. Find the length of base WX\r<BR>\n" );
document.write( "<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 #756427 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13209)</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=756427\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "Please take the time to look at your post before you submit it.  The trapezoid does not have a vertex D; there is no segment ZD.  It is clear that you must mean ZX... but we shouldn't have to figure that out.<br><BR>\n" );
document.write( "Here is a rough picture, approximately to scale....<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=drawing%28400%2C200%2C-15%2C15%2C-2%2C10%2C%0D%0Aline%280%2C0%2C12%2C0%29%2Cline%2812%2C0%2C4.5%2C6.6%29%2Cline%284.5%2C6.6%2C-12%2C6.6%29%2Cline%28-12%2C6.6%2C0%2C0%29%2Cline%280%2C0%2C4.5%2C6.6%29%2C%0D%0Alocate%280%2C-.5%2CZ%29%2Clocate%2812%2C-.5%2CY%29%2Clocate%284.5%2C8%2CX%29%2Clocate%28-12%2C8%2CW%29%2C%0D%0Alocate%286%2C-.5%2C12%29%2Clocate%289%2C3.3%2C10%29%2Clocate%28-4.5%2C8%2Cx%29%2Clocate%28-6.5%2C3%2C17%29%2Clocate%282.2%2C3.3%2C8%29%0D%0A%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "Angles YZX and WXZ are congruent -- parallel lines WX and YZ cut by transversal ZX.<br><BR>\n" );
document.write( "By the law of cosines in triangle XYZ,<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=10%5E2+=+8%5E2%2B12%5E2-2%2A8%2A12%2Acos%28theta%29 ALIGN=MIDDLE  ALT=\"10%5E2+=+8%5E2%2B12%5E2-2%2A8%2A12%2Acos%28theta%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%28theta%29+=+108%2F192+=+9%2F16 ALIGN=MIDDLE  ALT=\"cos%28theta%29+=+108%2F192+=+9%2F16\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "By the law of cosines in triangle WXZ,<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=17%5E2+=+x%5E2%2B8%5E2-2%2Ax%2A8%2Acos%28theta%29 ALIGN=MIDDLE  ALT=\"17%5E2+=+x%5E2%2B8%5E2-2%2Ax%2A8%2Acos%28theta%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=189+=+x%5E2%2B64-16x%289%2F16%29 ALIGN=MIDDLE  ALT=\"189+=+x%5E2%2B64-16x%289%2F16%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%5E2-9x-125+=+0 ALIGN=MIDDLE  ALT=\"x%5E2-9x-125+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "The quadratic expression does not factor; the quadratic formula gives us<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+%289+%2B+sqrt%2881%2B500%29%29%2F2 ALIGN=MIDDLE  ALT=\"x+=+%289+%2B+sqrt%2881%2B500%29%29%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "which, to a few decimal places, is x = 16.552.<br><BR>\n" );
document.write( "ANSWER: The length of base WX is approximately 16.552.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );