Given data:
The first length is XZ=28.
The second length is KL = 42.
The third side of triangle is YZ = 76.
If line passing through the mid points of the two sides of the triangle then the given line is half of the third side.
[tex]\begin{gathered} KL=\frac{1}{2}XY \\ XY=2(KL) \end{gathered}[/tex]Substitute the given value in the above expression.
[tex]\begin{gathered} XY=2(42) \\ =84 \end{gathered}[/tex]The expression for JY is,
[tex]JY=\frac{1}{2}XY[/tex]Substitute 84 for XY in the above expression.
[tex]\begin{gathered} JY=\frac{1}{2}(84) \\ =42 \end{gathered}[/tex]The expression for JK is,
[tex]JK=\frac{1}{2}(YZ)[/tex]Substitute 76 for YZ in the above expression.
[tex]\begin{gathered} JK=\frac{1}{2}(76) \\ =38 \end{gathered}[/tex]Thus, the value of XY is 84, the value of JY is 42, and the value of JK is 38.