calculate the slope m using the gradient formula
m = (y₂ - y₁ ) / (x₂ - x₁ )
with (x₁, y₁ ) = J(- 3, 2 ) and (x₂, y₂ ) = K(4, - 1 )
= = -
with (x₁, y₁ ) = L(2, - 5 ) and (x₂, y₂ ) = K(4, - 1 )
= = = 2
Similarly
= = -
= = = 2
JKLM is a parallelogram because both pairs of opposite sides are parallel