Answer: A) 7.2 feet
The value is approximate.
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Step-by-step explanation:
Check out the diagram below.
The angle of depression being 31 degrees refers to the idea of looking straight horizontal, then looking down 31 degrees. I recommend adding a dashed horizontal line.
That horizontal line is parallel to the ground. This forms a pair of congruent alternate interior angles. Therefore, we have two angles that are 31 degrees as the diagram shows.
The 31 degrees at the bottom is the angle of elevation.
Use this angle of elevation to say...
tan(angle) = opposite/adjacent
tan(31) = x/12
x = 12*tan(31)
x = 7.210327 approximately
This rounds to 7.2 feet