document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=650170>Question 650170</A>: <I><SPAN STYLE=\"word-break: break-all;\"> use slopes to show that the quadrilateral whose vertices are (1.-1), (4,1),(2,2), and (5,4) is a parallelogram </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #407204 by </B><A HREF=/tutors/aboutme.mpl?userid=sachi><B>sachi(548)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=sachi><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=sachi><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=407204\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> let the vertices of a quadrilateral   are A(1.-1), B(4,1),C(2,2), and D(5,4) <BR>\n" );
document.write( "then slope AB=[1-(-1)]/[4-1]=2/3<BR>\n" );
document.write( "slope CD=[4-2]/[5-2]=2/3<BR>\n" );
document.write( "so AB parallel to CD<BR>\n" );
document.write( "now<BR>\n" );
document.write( "slope AC=[2-(-1)]/[2-1]=3<BR>\n" );
document.write( "slope BD=[4-1]/[5-4]=3<BR>\n" );
document.write( "so AC parallel to BD<BR>\n" );
document.write( "so ABCD is a parallelogram<BR>\n" );
document.write( "ans </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );