WAEC Mathematics 2016 Objective — Question 27
Question 27 of 50 from the West African Examinations Council (WAEC) Mathematics 2016 Objective paper, with the correct answer and a full explanation.
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27. If cosθ=x and sin60°=x+0.5, 0°<θ<90°, find, correct to the nearest degree, the value of θ°. A. 96° B. 57° C. 60° D. 69°
- A. 96°
- B. 57°
- C. 60°
- D. 69°Correct
Explanation
sin60°=cos(90°-60°)=cos30°=√3/2=x+0.5 → x=(√3-1)/2=0.366=cosθ → θ=cos⁻¹(0.366)≈69°.
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