A person is watching a boat from the top of a lighthouse. The boat is approaching the lighthouse directly. When first noticed the angle of depression to the boat is 13°7'. When the boat stops, the angle of depression is 50°42' . The lighthouse is 200 feet tall. How far did the boat travel from when it was first noticed until it stopped? Round your answer to the hundredths place.
I just need to know how to solve the bases of the triangle. I don't know which trig function to use.

Question

A person is watching a boat from the top of a lighthouse. The boat is approaching the lighthouse directly. When first noticed the angle of depression to the boat is 13°7'. When the boat stops, the angle of depression is 50°42' . The lighthouse is 200 feet tall. How far did the boat travel from when it was first noticed until it stopped? Round your answer to the hundredths place. 
I just need to know how to solve the bases of the triangle. I don't know which trig function to use.

anonymous · Answer

The distance the boat travel is d = d₁ - d₂
d₁ is distance with the angle of 13°7'
d₂ -------------------------------------- 50°42'

anonymous · Answer

I know! I just need to know which trig function to use. Or maybe I am very confused.

anonymous · Answer

Can you see the relations now?

anonymous · Answer

Yes. I had confused myself because I thought the angles given were the top ones >__<  Thank you!

anonymous · Answer

So you understand now?