The surface area is ![404.8\ in^{2}](/tpl/images/0423/7083/5c2e3.png)
Step-by-step explanation:
we know that
The surface area of the figure is equal to
![SA=2B+PL](/tpl/images/0423/7083/09608.png)
where
B is the area of the trapezoidal face
P is the perimeter of the trapezoidal face
L is the length of the figure
Find the area of B
![B=\frac{1}{2}(15+5)8\\ \\B=80\ in^{2}](/tpl/images/0423/7083/2167c.png)
Find the perimeter P
![P=(8+5+12.8+15)=40.8\ in](/tpl/images/0423/7083/d0faa.png)
we have
![L=6\ in](/tpl/images/0423/7083/a850c.png)
substitute the values
![SA=2(80)+(40.8)(6)=404.8\ in^{2}](/tpl/images/0423/7083/f1dec.png)