Exercise 23 Page 668

We are asked to determine if either Terrence or Rodrigo is correct when they try to determine the relationship between the angles of elevation and depression. Let's try to draw the situation they use to prove their answers.

Since the horizontal lines of sight from both people are parallel to each other, the angles of elevation and depression are congruent according to the Alternate Interior Angles Theorem.

Therefore, if we are looking up at someone with an angle of elevation of 35^(∘), then they are looking down at us with an angle of depression of 35^(∘). This means that Rodrigo is correct in his reasoning and Terrence is not.