You are looking at a billboard 40 m away with an angle of elevation of 30°. At what height is the billboard?

A 20

B 30

C 40

D 80

Correct Answer: Option A

ধরি, বিলবোর্ডটির উচ্চতা = x মি.
∴ sin30° = x/40 [যেখানে sin θ = লম্ব/অতিভুজ]
→ 1/2 = x/40
→ 2x = 40
→ x = 20 মি.