please help me on this

Answer:
YZ = 8.5
Step-by-step explanation:
Since RY is an angle bisector then the ratio of the sides of the triangle are equal to the corresponding ratio of the base, that is
[tex]\frac{YX}{YZ}[/tex] = [tex]\frac{XR}{ZR}[/tex] , substitute values
[tex]\frac{11.9}{YZ}[/tex] = [tex]\frac{7}{5}[/tex] ( cross- multiply )
7YZ = 59.5 ( divide both sides by 7 )
YZ = 8.5