Expert: Sherry Wallin - 4/19/2010

Question
I'm not sure if it matters what degree the "angle on depression" has to be... This is a question in 9th grade geometry but its also Trig. If it does matter can it only exceed to 90degrees?
Actual Q: True or False: An angle of depression can never be more than 90°.


Thank you

Brittni

Answer
Hi Brittni~
    One definition of the angle of depression is: the angle of depression is the angle between the horizontal and the line of sight to an object beneath the horizontal. So it is always measured from the horizontal which is from the x-axis (either side but generally from the positive x-axis).
Suppose you are on the x-axis and you are looking down on an object below the x-axis. The angle your line of sight makes with the x-axis is the angle of depression. If you are at the origin and you are facing the positive x-axis then you want any angle that is less than or equal to the vertical (straight down). If it were more than the vertical then you would be facing the negative x-axis and it could only be up to the vertical fall. I hope this makes sense. This means that from the positive x-axis the most the depression could be is 90 degrees and if for some reason it was more than 90 degrees you would be measuring it from the negative x-axis, thus it can never be more than 90 degrees.

Math Prof