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Explanation:
Use the slope formula to find the slope of AB
m = (y2-y1)/(x2-x1)
m = (3-8)/(2-(-3))
m = (3-8)/(2+3)
m = -5/5
m = -1
The slope of line AB is -1
Do the same for the points C and D
m = (y2-y1)/(x2-x1)
m = (2-6)/(-8-(-4))
m = (2-6)/(-8+4)
m = (-4)/(-4)
m = 1
The slope of line CD is 1
The two slopes -1 and 1 multiply to -1, which indicates AB is perpendicular to CD. The two lines form a 90 degree angle.
