Consider all angles whose reference angle is 45° with terminal sides not in Quadrant I.The angles that share the same cosine value as cos 45° have terminal sides in quadrant IIIIIIV(none of the quadrants).

The cosine of 45° is positive: cos 45° = √2/2. Cosine is positive in Quadrants I and IV, and the question excludes Quadrant I. So the angles with the same cosine value have terminal sides in Quadrant IV, choice C.

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