Answer:
Question (a)
Midpoint of a line segment:
[tex]M=\left(\dfrac{x_1+x_2}{2},\dfrac{y_1+y_2}{2}\right)[/tex]
Given:
[tex]\implies \textsf{midpoint of }JL=\left(\dfrac{-2+4}{2},\dfrac{2+0}{2}\right)=(1,1)[/tex]
Given:
[tex]\implies \textsf{midpoint of }MK=\left(\dfrac{3-1}{2},\dfrac{7-5}{2}\right)=(1, 1)[/tex]
Question (b)
Find slopes (gradients) of JL and MK then compare. If the product of the slopes of JL and MK equal -1, then JL and MK are perpendicular.
[tex]\textsf{slope }m=\dfrac{y_2-y_1}{x_2-x_1}[/tex]
Given:
[tex]\implies \textsf{slope of }JL=\dfrac{0-2}{4+2}=-\dfrac13[/tex]
Given:
[tex]\implies \textsf{slope of }MK=\dfrac{-5-7}{-1-3}=3[/tex]
[tex]\textsf{slope of }JL \times \textsf{slope of }MK=-\dfrac13 \times3=-1[/tex]
Hence segments JL and MK are perpendicular