Question 3
TrigonometryIf cos x = −0.7133, find the values of x between 0° and 360°.
- A.44.5°, 224.5°
- B.123.5°, 190.5°
- C.135.5°, 213.5°
- D.135.5°, 224.5°
Show the answer and explanation
Answer: D (135.5°, 224.5°)
Explanation
The reference angle is cos⁻¹ 0.7133 ≈ 44.5°. Cosine is negative in the 2nd and 3rd quadrants: 180° − 44.5° = 135.5° and 180° + 44.5° = 224.5°.