Examveda

If θ is acute angle and sin(θ + 18°) = $$\frac{1}{2}$$, then the value of θ in circular measure is:

A. $$\frac{\pi }{{12}}$$ Radians

B. $$\frac{\pi }{{15}}$$ Radians

C. $$\frac{{2\pi }}{5}$$ Radians

D. $$\frac{{3\pi }}{{13}}$$ Radians

Answer: Option B

Solution (By Examveda Team)

$$\eqalign{ & \sin \left( {\theta + 18} \right) = \frac{1}{2} \cr & \sin \left( {\theta + 18} \right) = \sin 30 \cr & \theta + 18 = 30 \cr & \therefore \theta = 12 \cr & {\text{We know that}} \cr & {180^ \circ } = \pi \cr & {12^ \circ } = \frac{\pi }{{180}} \times 12 = \frac{\pi }{{15}} \cr} $$

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