Question

12. A boat is on the same horizontal
level as the foot of a cliff, and the
angle of depression of the boat
from the top of the cliff is 30°. If
the boat is 120m away from the
foot of the cliff, find the height of
the cliff correct to three significant
figures.​

Answer 1

Answer:

69.28 m

Step-by-step explanation:

Angle at boat = 30°

Angle at Top of Cliff to Boat = 60°

Angle at bottom of cliff to boat = 90°

Distance between boat and cliff = 120m

Angle opposite to Cliff from boat is 30°

Angle opposite to Distance between boat and cliff is 60°

Therefore height of cliff = 120/1.732 = 69.28m

Answer 2

Answer:

69.3m

Step-by-step explanation:

Since the angle of depression casted is 30 degree and the boat is 120 m away from the foot of cliff

thus,

tan 30= Height of cliff

             Distance of boat from cliff

1/$\sqrt{3\\}$= Height of cliff/ 120

Therefor, height of cliff= 120/$\sqrt{3}$=69.364 m

Rounding of we get 69.3 m