Final answer:
Without additional context, it's impossible to determine the measure of angle Y solely based on the provided measures of angles X and Z.
Step-by-step explanation:
The question seems to be asking for the measure of an angle denoted as m∠Y. However, without more context, such as additional angles or the relationship between angles X, Y, and Z, it's not possible to provide a definite answer. For instance, if angles X, Y, and Z are part of a triangle, we could use the fact that the sum of the interior angles of a triangle is always 180° to find m∠Y. But without such context, it's important not to make assumptions about the relationship between these angles.
For example, if they were indeed in a triangle, the calculation would be m∠Y = 180° - m∠X - m∠Z, which would equal 180° - 34° - 26° = 120°. However, this is specific to the scenario where the angles are part of a triangle, and we do not have enough information to confirm this is the case for this question.