document.write( "Question 1139131: Prove that the quadrilateral formed by connecting the midpoints of the sides of quadrilateral ABCD is a parallelogram. \n" ); document.write( "
Algebra.Com's Answer #756917 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
\r\n" );
document.write( "\r\n" );
document.write( "All you need do is to draw one diagonal, say, PR.\r\n" );
document.write( "\r\n" );
document.write( " \r\n" );
document.write( "\r\n" );
document.write( "Then AD is a midline of triangle PRS and thus parallel to and half\r\n" );
document.write( "the length of PR. \r\n" );
document.write( "\r\n" );
document.write( "Similarly, BC is a midline of triangle PRQ and is \r\n" );
document.write( "thus ALSO parallel to and half the length of PR.  So AD and BC are both>\r\n" );
document.write( "parallel and equal in length.  That's enough to prove ABCD is a \r\n" );
document.write( "parallelogram.  Now go write that up in a two-column proof.\r\n" );
document.write( "\r\n" );
document.write( "Edwin

\n" ); document.write( " \n" ); document.write( "
\n" );