Question 238600
Use slopes to show that the square with virtices at (-2,5), (4, 5), (4, -1), and (-2, -1) has diagonals that are perpendicular. 
----------------------
Plot the points on a coordinate system so you can see where the
end points of the diagonals are.
----
1st pair is (-2,5),(4,-1)
slope of that segment is (-1-5)/(4--2) = -6/6 = -1
------------------------------------
2nd pair at (4,5),(-2,-1)
slope of that segment is (-1-5)(-2-4) = -6/-6 = 1
--------------------------------------
Since the product of the slopes is -1, the diagonals are perpendicular
to one another.
=======================================
Cheers,
Stan H.