We need to find the area of a semi-circle with a diameter d = 7.4''.
The area of a circle with radius r is

Thus, the area A of a semi-circle with radius r is

Step 1
Find the radius of the semi-circle. The radius is half the diameter d. So, we have:

Step 2
Use this result to find the area A of the semi-circle:

Answer
Therefore, the area of the figure, rounded to the nearest tenth, is 21.5 in².