Answer: 38.7°
Explanation:
Hi, since the situation forms a right triangle (see attachment) we have to apply the next trigonometric function.
Tan α = opposite side / adjacent side
Where α is the angle of elevation of the sun (x), and the opposite side is the height of the pole, and the adjacent side is the length of the shadow.
Replacing with the values given:
Tan x = 16/20
x = arc tan 0.8
x= 38.7°
Feel free to ask for more if needed or if you did not understand something.