The diagram shows the locations of john and mark in relationship to the top of a tall building labeled a. a) describe < 4 as it relates to the situation b) describe < 3 as it relates to the situation

Given that the diagram shows the location of John and Mark in relationship to the top of the building labeled A, then:
a]
∠4 is the angle of elevation as seen by Mark from his location. It is the angle between the horizontal and the line from the object to the observer's eyes.

b]
∠3 is the angle of depression and it is congruent to the angle 5, which is the angle of elevation as seen by John from his location.