Question 843125
<pre><font face = "Tohoma" size = 3 color = "indigo"><b> 
Hi,
If 
*[tex \LARGE \ \ \ \ \ \ \ \ \ \ \overline{WX}\ \parallel\ \overline{ZY}] and *[tex \LARGE \overline{YW}\ \parallel\ \overline{ZX}] 
then WXZY is a parallelogram.
(2,2)
(5,2)  m = 0 for WX and for ZY, m = 0
(6,-2)
(2,2)  m = -1 for ZX and for YW m = -1
{{{drawing(300,300,   -6, 6, -6, 6, grid(1), 
circle(2, 2,0.2),
locate(1.5, 2.5,"W"),
circle(5, 2,0.2),
locate(5.5, 2.5,"X"),
circle(3, -2,0.2),
locate(2.5, -2.5,"Y"),
circle(6, -2,0.2),
locate(6, -2.5,"Z"),
graph( 300, 300, -6, 6, -6, 6))}}}