The answer is 2/5, which is 2 over 5
The area is the area of the rectangle minus the semicircle.
The radius is 8 mm, and the length of the rectangle is 16 mm, the diameter.

27.52 mm²
The answer to your question is: 60.3°
Data
height = 7 m
shadow = 4 m
angle = ?
Process
tangent Ф = opposite side / adjacent side
tangent Ф = 7 / 4
tan Ф = 1.75
Ф = 60.3°