Answer:
=
412
feet
Step-by-step explanation:
The angle of depression is always measured from the horizontal.
A triangle is formed by the lighthouse, the ground and the boat. The angle of depression is not in the triangle, but it is equal to the angle of elevation at the boat. (Alternate angles on parallel lines)
The angle at the top of the lighthouse, inside the triangle is:
90°−27°
=63°
The distance to the boat is the side opposite the angle of
63°
while the height of the lighthouse is the adjacent side.
opposite
adjacent
=tan 63°
distance
210=tan 63°
distance=210×tan 63°=412 feet