Hello!
The surface area is the area of all of the shapes on the net added up. First we will find the area of the two triangles.
A=0.5bh
A=0.5(3·6)
A=0.5(18)
A=9
Since there are two triangles we double this area, giving us 18.
Now let's find the length of the two side rectangles.
7(4)=28
28+28=56
Now to find the middle rectangle.
6(7)=42
Now we add up all of the area to find the surface area.
42+56+18=116
The surface area is 116 cm².
I hope this helps!