What you need to know for this question is how Y relates to X. (feel free to stop reading when you want to attempt on your own)
How many degrees are in a triangle? How many total degrees are in the angle made up by Y and it's unlabeled missing adjacent angle?
How can you use this knowledge towards solving the problem?
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First step toward solution:
set up an equation representing the summation of all angles inside the triangle, and the numerical value of degrees to which they are equal.
