From the picture you can see that TY bisects angle T.
Use the bisector property:
[tex] \dfrac{TK}{KY} =\dfrac{TV}{VY} [/tex].
If YK=68 mm and VK=x mm, then VY=x-68 mm.
Then [tex] \dfrac{129.2}{68} =\dfrac{57}{x-68} [/tex].
Express x-68:
[tex] x-68=\dfrac{57\cdot 68}{129.2}=30 [/tex] mm.
Therefore, x=30+68=98 mm.
Answer: x=98 mm.
