just confused on this

Question

A boat is 1000 meters from the base of a cliff that is 180 m tall.  

What is the angle of depression, ∠a, from the top of the cliff to the boat?  

Round your answer to the nearest tenth.

Answer 1

You must draw pictures in order to understand the problem....

Boat a point B.

base of the cliff at C.

So BC=1000

top of the cliff at point A, so AC=180

Then Right triangle BCA has legs 1000 and 180.

the angle of depression is congruent to angle ABC (by parallel lines)

tan ABC = 180/1000 = 0.18

the angle is inverse_tangent (0.18) = 10.2 degrees