PLEASE HELP!!! I tried using different formulas, adding, subtracting, dividing, multiplying you name it and I have yet to find the correct answer. How would I should this problem?

Answer:
19.14
Step-by-step explanation:
You have a half circle and a square, look at them separate then add for the area.
Circle
Your radius is half the diameter, so 4/2
Radius = 2
[tex]A = 3.14 * radius\\A = 3.14 * 2\\A = 6.28[/tex]
This is for the entire circle, half of that would be 3.14
Square
[tex]A = 4^{2} \\A = 16[/tex]
Add them both together for a total area of 19.14 square miles