Answer:
X || Z
Step-by-step explanation:
We are not told about any lines being perpendicular, so we cannot conclude any lines to be perpendicular.
Theorem:
If two lines are parallel to the same line, then the two lines are parallel to each other.
X is paralle to Y; Z is parallel to Y.
Line X and Z are parallel to the same line, Y, so lines X and Z are parallel.
Answer: X || Z
