Hello, haftakhan!
I have difficulty reading the numbers.
I'll explain the surface area of the first one.
Code:
*
* *
* * 20
* *
* * *
* * *
12 * * *
* * *
* * * 14
* * * * * * * * *
16
The front face is a right triangle with base 16 and height 12.
. . Its area is: .$\displaystyle \tfrac{1}{2}(16)(12) \:=\:96$
The rear face is identical.
. . $\displaystyle \text{Area(front and rear)} \:=\:2\cdot96 \:=\:192$
The left face is a $\displaystyle 14\times12$ rectangle.
. . $\displaystyle \text{Area(left)} \;=\;14\cdot12 \;=\;168$
The sloping right face is a $\displaystyle 14\times 20$ rectangle.
. . $\displaystyle \text{Area(right)} \;=\;14\cdot20 \;=\;280$
The bottom face is a $\displaystyle 16 \times 14$ rectangle.
. . $\displaystyle \text{Area(bottom)} \;=\;16\cdot14 \:=\:224$
Total surface area: .$\displaystyle 192 + 168 + 280 + 224 \;=\;864\text{ units}^2$