A lighthouse is 15m above sea level.

The lighthouse operator sights a boat at an angle of depression of 25 degrees.

How far is the boat from the lighthouse?

Round your answer to the nearest tenth.

For this you will use the tangent function. You have the adjacent side and have to find the opposite side.

tan x = opposite/adjacent

tan 25 = x/15

15 (tan 25) = x

6.9946 = x

So the boat is approximately 6.9946 m away from the lighthouse.