In order to calculate the total surface area we just need to sum the area of the different faces.
From the picture we see that we have the following faces.
- 2 x A (two triangles)
- S (a rectangle)
- T (a rectangle)
- B (the base rectangle)
Now me calculate the area of each one:
![A\text{ = }(1)/(2)\cdot12\cdot5\text{ = }30](https://img.qammunity.org/2023/formulas/mathematics/college/ki7n274djkqv3v3zmkmlvyawn02vfjlxx7.png)
![S\text{ = 5}\cdot5=\text{ 25}](https://img.qammunity.org/2023/formulas/mathematics/college/n9l2vgx5w1zb8vjxd0a12f1e6186d8brip.png)
![B=12\cdot5=60](https://img.qammunity.org/2023/formulas/mathematics/college/re3l5002h45ye6iys37pg1b0dgxjpad7m7.png)
![T=13\cdot5=65](https://img.qammunity.org/2023/formulas/mathematics/college/l9raxl74ofcal9gge1m80fbhlp3b65tffx.png)
Now that we have the area of each face, we sum all the areas, taking in account the ones that appears twice:
![\text{Total area = 2}\cdot A+S+T+B=2\cdot30+25+60+65=210](https://img.qammunity.org/2023/formulas/mathematics/college/yku7sy81kufxzlcoj1l6mw0y7r3bkihb8a.png)
And, because the lenghts are measured in ft, the final answer is:
![\text{Total area = 210 ft}^2](https://img.qammunity.org/2023/formulas/mathematics/college/p49yn23p3ar6r4memxz5c6r4jvvyq3dqyg.png)
Note:
![\text{Area of a triangle = }(1)/(2)\cdot\text{base}\cdot\text{height}](https://img.qammunity.org/2023/formulas/mathematics/college/i3dfpbtsr2drobf200qrg4a8ag6yo2t9u3.png)
![\text{Area of a rectangle = base }\cdot\text{ height}](https://img.qammunity.org/2023/formulas/mathematics/college/cnaibbnav0xovlg4wso7a5zxqvsb08gbxs.png)