Question

The angle of depression from D to F measures 40°. If DE = 100 m, find DF. Round your answer to the nearest tenth.

Answer 1

You need to draw the triangle DEF with a right angle at E.  Angle D = 40 and DE = 100 m.  Once you have marked up your triangle, you can use cosine to find DF.  

Answer 2

The correct answer is 130.5