Answer:
30.9 cm²
Explanation:
To find the surface area of this figure, we find the area of the base and the 3 identical sides.
The base is split into two identical right triangles. Let's find the area of one and multiply by two.
Half of 3: 1.5

There are two right triangles:

The area of one of the sides will be the same thing, except the height is 6.

There are 3 sides identical to this one:
.
Add 27 and 3.9:

Hope this helped!