Answer:
The height of the cliff CD is approximately 539.76 m
Explanation:
The given parameters are;
The first angle of elevation with which the captain sees the person on the cliff = 61°
The second angle of elevation with which the captain sees the person on the cliff after moving 92 m closer to the cliff = 69°
The angle made by the adjacent supplementary angle to the second angle of elevation = 180° - 69° = 111°
∴ Whereby, the rays from the first and second angle of elevation and the distance the ship moves closer to the cliff forms an imaginary triangle, we have;
The angle in the imaginary triangle subtended by the distance the ship moves closer to the cliff = 180° - 111° - 61° = 8°
By sine rule, we have;
AB/(sin(a)) = BC/(sin(c))
Which gives;
92/(sin(8°)) = BC/(sin(61°))
BC = (sin(61°)) × 92/(sin(8°)) ≈ 578.165 m
BC ≈ 578.165 m
The height CD = BC × sin(69°)
∴ The height of the cliff CD = 578.165 m × sin(69°) ≈ 539.76 m.
The height of the cliff CD ≈ 539.76 m.