To obtain the area of the composite figure, the following steps are necessary:
Step 1: Recall the formulas for the area of a rectangle and a triangle (since they both make up the composite figure), as given below:
![\begin{gathered} A_(rec\tan gle)=length\text{ }* width \\ A_(triangle)=(1)/(2)* base* height \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/zr46io53uve8crm5gjhoq7rhzqra051z2k.png)
Step 2: Compute the areas of the rectangle and triangle using the formulas above
![\begin{gathered} A_(rec\tan gle)=length\text{ }* width \\ \Rightarrow A_(rec\tan gle)=7\text{ }*6=42 \\ A_(triangle)=(1)/(2)* base* height \\ \Rightarrow A_(triangle)=(1)/(2)*3*6=(18)/(2)=9 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/quvpm20g6yotnyuy2qnw18n6itrw7rclpy.png)
Step 3: Add the two areas together, as follows:
![A_(composite)=A_(rec\tan gle)+A_(triangle)](https://img.qammunity.org/2023/formulas/mathematics/college/e6ug6sva0k8pk0527icqw44ws7zeccbwym.png)
Thus:
![\begin{gathered} A_(composite)=42+9=51 \\ \Rightarrow A_(composite)=51in^2 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/mrciltz7zxc2r0snknj4x9oxsgf4v739b9.png)
Therefore, the area of the composite figure is 51 inches squared (option A)