The two triangle here are similar.
How?
SSS similarity criteria.
Now,
since WZ is a midpoint.
VX = 2VW
VX/VW =2
The same ratio will be applicable on the other sides of traingle.
Now,
[tex] \frac{XY}{WZ} = 2[/tex]
Substituting the given values for XY and WZ are:
[tex] \frac{u}{u - 3} = 2 \\ u = 2u - 6 \\ - u = - 6 \\ u = 6[/tex]
Therefore u =6.
