Question 916718:  The points (-4, -3), (1,4), (4, 2) and (-1, -5) are vertices of a quadrilateral. Use slopes to explain why the quadrilateral is a parallelogram. 
 Answer by jim_thompson5910(35256)      (Show Source): 
You can  put this solution on YOUR website! Hint:
 
 
Let's label the points A,B,C,D
 
 
A = (-4, -3) 
B = (1,4) 
C = (4, 2) 
D = (-1, -5)
 
 
If you can show that segment AB is parallel to segment CD
 
 
AND
 
 
If you can show that segment BC is parallel to segment AD
 
 
then ABCD is a parallelogram. Use the slope formula   to calculate the slopes. 
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