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
![\pi r^(2)](https://img.qammunity.org/2023/formulas/mathematics/high-school/s3ashw0dnwrqrd0lbb8pi7pvw5pr297jla.png)
Thus, the area A of a semi-circle with radius r is
![A=(\pi r^(2))/(2)](https://img.qammunity.org/2023/formulas/mathematics/middle-school/1rj5f0311xbk7ex8ehtceu313w90ewgix1.png)
Step 1
Find the radius of the semi-circle. The radius is half the diameter d. So, we have:
![r=(d)/(2)=(7.4^(\doubleprime))/(2)=3.7^(\doubleprime)=3.7\text{ in}](https://img.qammunity.org/2023/formulas/mathematics/college/e5eoh6utoy5cu1wl5bp67i0bmtaa7zy1g2.png)
Step 2
Use this result to find the area A of the semi-circle:
![A=(\pi)/(2)(3.7^{}in)^2=(\pi13.69)/(2)in^2=6.845\pi in^2\cong21.5in^2](https://img.qammunity.org/2023/formulas/mathematics/college/fmk2kbn5wi92kt9oxecs0itx68jo2uz83q.png)
Answer
Therefore, the area of the figure, rounded to the nearest tenth, is 21.5 inĀ².