Question

Which of the following correctly uses the special triangles on the unit circle to determine θ
in degrees when cosθ=2√2
? You may assume that 0°≤θ≤180°
.

(1 point)
Responses

30°
30 degrees

90°
90 degrees

60°
60 degrees

45°
45 degrees
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Answer 1

45°

Reason: On the unit circle the 45° (45–45–90) special triangle gives cos45° = √2/2. (Note: cosθ = 2√2 is impossible since |cosθ| ≤ 1, so the problem likely meant cosθ = √2/2.)