Answer: They are not perpendicular because their slopes are not negative reciprocals.
Explanation:
For these two lines to be perpendicular, their slopes have to be negative reciprocals.
Slope of FG.
F = (-4, 1)
G = (0, -2)
= (Y₂ - Y₁) / (X₂ - X₁)
= (-2 - 1) / (0 + 4)
= -3/4
Slope of HJ
J = (0 , 4)
H = (-4, -2)
Slope = (Y₂ - Y₁) / (X₂ - X₁)
= (-2 - 4) / (-4 -0)
= 6/4
= 3/2
The slopes of these lines are not negative reciprocals so these lines are not perpendicular.