Answer:
x > 90 > y
Explanation:
You want to know the relationship of the central angles in a rectangle where the diagonals cross.
Angle relations
Assuming we can trust the figure (not always a good idea), we notice that x° is an obtuse angle and y° is an acute angle. (The angle opposite the longer side in this geometry will always be obtuse.)
This means ...
x° > 90°
90° > y°
The two angles form a linear pair, so their sum is 180°.
The correct description is ...
x > 90 > y
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Additional comment
If the diagonals crossed at right angles, the rectangle would be a square.