Question 1205075
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I agree with tutor Ikleyn. The phrasing "the distance from you to the dinosaur is 8,500ft" tells us that the hypotenuse is 8500 ft; but the hypotenuse must be the longest side of the right triangle.


If it was instead phrased as "the <font color=red><u>horizontal</u></font> distance from you to the dinosaur is 8500 ft", then tutor Theo's drawing would apply.


However, Theo appears to have misinterpreted what an angle of depression is. 
Angle x of his drawing is NOT the angle of depression. 


The angle of depression results when you first look horizontally and then look down at your target. 
Here's an example
<img width=300 src = "https://www.mathsisfun.com/geometry/images/angle-elevation.svg">
Image Source
<a href="https://www.mathsisfun.com/definitions/angle-of-depression.html">https://www.mathsisfun.com/definitions/angle-of-depression.html</a>


We must subtract the x value that Theo got from 90 to get the angle of depression.
90 - x = 90 - 29.54 = 60.46  
Or we could compute it like this
arctan(15000/8500) = 60.46 approximately
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