9514 1404 393
Answer:
90°
Step-by-step explanation:
Any corner angle in a rectangle is 90°. Rotating the figure does not change that. Angle O' = 90°.
_____
Additional comment
No rigid transformation (translation, rotation, reflection) changes any angles. Nor does uniform dilation (the kind we usually study). Hence any rectangle that is translated, rotated, reflected, or dilated will still have all angles measuring 90°.
